diff --git a/blockchain/v0/reactor_test.go b/blockchain/v0/reactor_test.go
index a31c9a141..bddbb3f3b 100644
--- a/blockchain/v0/reactor_test.go
+++ b/blockchain/v0/reactor_test.go
@@ -13,6 +13,7 @@ import (
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	cfg "github.com/tendermint/tendermint/config"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/mock"
 	"github.com/tendermint/tendermint/p2p"
@@ -82,7 +83,7 @@ func newBlockchainReactor(
 	fastSync := true
 	db := dbm.NewMemDB()
 	blockExec := sm.NewBlockExecutor(db, log.TestingLogger(), proxyApp.Consensus(),
-		mock.Mempool{}, sm.MockEvidencePool{})
+		mock.Mempool{}, evmock.NewDefaultEvidencePool())
 	sm.SaveState(db, state)
 
 	// let's add some blocks in
diff --git a/blockchain/v1/reactor_test.go b/blockchain/v1/reactor_test.go
index 0e6f21222..a82b2211c 100644
--- a/blockchain/v1/reactor_test.go
+++ b/blockchain/v1/reactor_test.go
@@ -16,6 +16,7 @@ import (
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	cfg "github.com/tendermint/tendermint/config"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/mock"
 	"github.com/tendermint/tendermint/p2p"
@@ -112,7 +113,7 @@ func newBlockchainReactor(
 	fastSync := true
 	db := dbm.NewMemDB()
 	blockExec := sm.NewBlockExecutor(db, log.TestingLogger(), proxyApp.Consensus(),
-		mock.Mempool{}, sm.MockEvidencePool{})
+		mock.Mempool{}, evmock.NewDefaultEvidencePool())
 	sm.SaveState(db, state)
 
 	// let's add some blocks in
diff --git a/blockchain/v2/reactor_test.go b/blockchain/v2/reactor_test.go
index 3cc3c4426..aaa5c979d 100644
--- a/blockchain/v2/reactor_test.go
+++ b/blockchain/v2/reactor_test.go
@@ -15,6 +15,7 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/behaviour"
 	cfg "github.com/tendermint/tendermint/config"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/mock"
@@ -152,7 +153,7 @@ func newTestReactor(p testReactorParams) *BlockchainReactor {
 			panic(errors.Wrap(err, "error start app"))
 		}
 		db := dbm.NewMemDB()
-		appl = sm.NewBlockExecutor(db, p.logger, proxyApp.Consensus(), mock.Mempool{}, sm.MockEvidencePool{})
+		appl = sm.NewBlockExecutor(db, p.logger, proxyApp.Consensus(), mock.Mempool{}, evmock.NewDefaultEvidencePool())
 		sm.SaveState(db, state)
 	}
 
@@ -494,7 +495,7 @@ func newReactorStore(
 
 	db := dbm.NewMemDB()
 	blockExec := sm.NewBlockExecutor(db, log.TestingLogger(), proxyApp.Consensus(),
-		mock.Mempool{}, sm.MockEvidencePool{})
+		mock.Mempool{}, evmock.NewDefaultEvidencePool())
 	sm.SaveState(db, state)
 
 	// add blocks in
diff --git a/consensus/common_test.go b/consensus/common_test.go
index f8055f01c..e98c66837 100644
--- a/consensus/common_test.go
+++ b/consensus/common_test.go
@@ -26,6 +26,7 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	cfg "github.com/tendermint/tendermint/config"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	"github.com/tendermint/tendermint/libs/log"
 	tmos "github.com/tendermint/tendermint/libs/os"
@@ -373,7 +374,7 @@ func newStateWithConfigAndBlockStore(
 	}
 
 	// mock the evidence pool
-	evpool := sm.MockEvidencePool{}
+	evpool := evmock.NewDefaultEvidencePool()
 
 	// Make State
 	stateDB := blockDB
diff --git a/consensus/reactor_test.go b/consensus/reactor_test.go
index aee222bbd..3c3eef7ed 100644
--- a/consensus/reactor_test.go
+++ b/consensus/reactor_test.go
@@ -225,6 +225,16 @@ func (m *mockEvidencePool) Update(block *types.Block, state sm.State) {
 	m.height++
 }
 func (m *mockEvidencePool) IsCommitted(types.Evidence) bool { return false }
+func (m *mockEvidencePool) IsPending(evidence types.Evidence) bool {
+	if m.height > 0 {
+		for _, e := range m.ev {
+			if e.Equal(evidence) {
+				return true
+			}
+		}
+	}
+	return false
+}
 
 //------------------------------------
 
diff --git a/consensus/replay.go b/consensus/replay.go
index 3d9d6614b..0245a5341 100644
--- a/consensus/replay.go
+++ b/consensus/replay.go
@@ -15,6 +15,7 @@ import (
 	//auto "github.com/tendermint/tendermint/libs/autofile"
 	dbm "github.com/tendermint/tm-db"
 
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/mock"
 	"github.com/tendermint/tendermint/proxy"
@@ -473,7 +474,7 @@ func (h *Handshaker) replayBlock(state sm.State, height int64, proxyApp proxy.Ap
 	block := h.store.LoadBlock(height)
 	meta := h.store.LoadBlockMeta(height)
 
-	blockExec := sm.NewBlockExecutor(h.stateDB, h.logger, proxyApp, mock.Mempool{}, sm.MockEvidencePool{})
+	blockExec := sm.NewBlockExecutor(h.stateDB, h.logger, proxyApp, mock.Mempool{}, evmock.NewDefaultEvidencePool())
 	blockExec.SetEventBus(h.eventBus)
 
 	var err error
diff --git a/consensus/replay_file.go b/consensus/replay_file.go
index b8b8c51da..e27584ba0 100644
--- a/consensus/replay_file.go
+++ b/consensus/replay_file.go
@@ -13,6 +13,7 @@ import (
 	dbm "github.com/tendermint/tm-db"
 
 	cfg "github.com/tendermint/tendermint/config"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/mock"
@@ -311,7 +312,7 @@ func newConsensusStateForReplay(config cfg.BaseConfig, csConfig *cfg.ConsensusCo
 		tmos.Exit(fmt.Sprintf("Error on handshake: %v", err))
 	}
 
-	mempool, evpool := mock.Mempool{}, sm.MockEvidencePool{}
+	mempool, evpool := mock.Mempool{}, evmock.NewDefaultEvidencePool()
 	blockExec := sm.NewBlockExecutor(stateDB, log.TestingLogger(), proxyApp.Consensus(), mempool, evpool)
 
 	consensusState := NewState(csConfig, state.Copy(), blockExec,
diff --git a/consensus/replay_test.go b/consensus/replay_test.go
index f886cdeeb..7fd4f9e6d 100644
--- a/consensus/replay_test.go
+++ b/consensus/replay_test.go
@@ -23,6 +23,7 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/crypto"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
 	mempl "github.com/tendermint/tendermint/mempool"
@@ -296,7 +297,7 @@ const (
 
 var (
 	mempool = mock.Mempool{}
-	evpool  = sm.MockEvidencePool{}
+	evpool  = evmock.NewDefaultEvidencePool()
 
 	sim testSim
 )
diff --git a/consensus/wal_generator.go b/consensus/wal_generator.go
index 422c3f73b..f14d11db3 100644
--- a/consensus/wal_generator.go
+++ b/consensus/wal_generator.go
@@ -15,6 +15,7 @@ import (
 
 	"github.com/tendermint/tendermint/abci/example/kvstore"
 	cfg "github.com/tendermint/tendermint/config"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/mock"
@@ -73,7 +74,7 @@ func WALGenerateNBlocks(t *testing.T, wr io.Writer, numBlocks int) (err error) {
 	}
 	defer eventBus.Stop()
 	mempool := mock.Mempool{}
-	evpool := sm.MockEvidencePool{}
+	evpool := evmock.NewDefaultEvidencePool()
 	blockExec := sm.NewBlockExecutor(stateDB, log.TestingLogger(), proxyApp.Consensus(), mempool, evpool)
 	consensusState := NewState(config.Consensus, state.Copy(), blockExec, blockStore, mempool, evpool)
 	consensusState.SetLogger(logger)
diff --git a/evidence/mock/pool_mock.go b/evidence/mock/pool_mock.go
new file mode 100644
index 000000000..9ba15807f
--- /dev/null
+++ b/evidence/mock/pool_mock.go
@@ -0,0 +1,124 @@
+package mock
+
+import (
+	"time"
+
+	sm "github.com/tendermint/tendermint/state"
+	"github.com/tendermint/tendermint/types"
+)
+
+// A quick and easy in-memory mock implementation of the evidence pool configured with both the standard exposed
+// functions and extra helper function to set up, operate and ultimately imitate the evidence pool in a testing
+// environment. Note: this mock does no validation. Do not test with large amounts of evidence
+type EvidencePool struct {
+	PendingEvidenceList   []types.Evidence
+	CommittedEvidenceList []types.Evidence
+	ExpirationAgeTime     time.Duration
+	ExpirationAgeBlock    int64
+	BlockHeight           int64
+	BlockTime             time.Time
+}
+
+// ------------------------ INSTANTIATION METHODS --------------------------------------
+
+func NewEvidencePool(height, expiryHeight int64, currentTime time.Time, expiryTime time.Duration) *EvidencePool {
+	return &EvidencePool{
+		[]types.Evidence{},
+		[]types.Evidence{},
+		expiryTime,
+		expiryHeight,
+		height,
+		currentTime,
+	}
+}
+
+func NewDefaultEvidencePool() *EvidencePool {
+	return NewEvidencePool(1, 1, time.Now(), time.Millisecond)
+}
+
+// ----------------------- EVIDENCE POOL PUBLIC METHODS --------------------------------
+
+func (p *EvidencePool) PendingEvidence(maxNum int64) []types.Evidence {
+	if maxNum == -1 || maxNum >= int64(len(p.PendingEvidenceList)) {
+		return p.PendingEvidenceList
+	}
+	return p.PendingEvidenceList[:maxNum]
+}
+
+func (p *EvidencePool) AddEvidence(evidence types.Evidence) error {
+	p.PendingEvidenceList = append(p.PendingEvidenceList, evidence)
+	return nil
+}
+
+func (p *EvidencePool) Update(block *types.Block, state sm.State) {
+	p.BlockHeight = block.Height
+	p.BlockTime = block.Time
+	p.MarkEvidenceAsCommitted(block.Height, block.Time, block.Evidence.Evidence)
+	p.RemoveExpiredEvidence()
+}
+
+func (p *EvidencePool) MarkEvidenceAsCommitted(height int64, lastBlockTime time.Time, evidence []types.Evidence) {
+	for _, ev := range evidence {
+		if p.IsPending(ev) {
+			p.RemovePendingEvidence(ev)
+		}
+		p.CommittedEvidenceList = append(p.CommittedEvidenceList, ev)
+	}
+}
+
+func (p *EvidencePool) IsPending(evidence types.Evidence) bool {
+	for _, ev := range p.PendingEvidenceList {
+		if ev.Equal(evidence) {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *EvidencePool) IsCommitted(evidence types.Evidence) bool {
+	for _, ev := range p.CommittedEvidenceList {
+		if ev.Equal(evidence) {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *EvidencePool) IsExpired(evidence types.Evidence) bool {
+	return evidence.Height()+p.ExpirationAgeBlock < p.BlockHeight &&
+		evidence.Time().Add(p.ExpirationAgeTime).Before(p.BlockTime)
+}
+
+// ------------------------------- HELPER METHODS --------------------------------------
+
+func (p *EvidencePool) RemovePendingEvidence(evidence types.Evidence) {
+	for idx, ev := range p.PendingEvidenceList {
+		if ev.Equal(evidence) {
+			p.PendingEvidenceList[idx] = p.PendingEvidenceList[len(p.PendingEvidenceList)-1]
+			p.PendingEvidenceList = p.PendingEvidenceList[:len(p.PendingEvidenceList)-1]
+			return
+		}
+	}
+}
+
+func (p *EvidencePool) RemoveExpiredEvidence() {
+	for _, evidence := range p.PendingEvidenceList {
+		if p.IsExpired(evidence) {
+			p.RemovePendingEvidence(evidence)
+		}
+	}
+}
+
+func (p *EvidencePool) AddMockEvidence(height int64, address []byte) types.Evidence {
+	mock := types.MockEvidence{
+		EvidenceHeight:  height,
+		EvidenceTime:    p.BlockTime,
+		EvidenceAddress: address,
+	}
+	_ = p.AddEvidence(mock)
+	return mock
+}
+
+func (p *EvidencePool) CommitEvidence(evidence types.Evidence) {
+	p.MarkEvidenceAsCommitted(evidence.Height(), evidence.Time(), []types.Evidence{evidence})
+}
diff --git a/state/execution_test.go b/state/execution_test.go
index 3af90f8a0..d8443100f 100644
--- a/state/execution_test.go
+++ b/state/execution_test.go
@@ -12,6 +12,7 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/secp256k1"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/mock"
 	"github.com/tendermint/tendermint/proxy"
@@ -38,7 +39,7 @@ func TestApplyBlock(t *testing.T) {
 	state, stateDB, _ := makeState(1, 1)
 
 	blockExec := sm.NewBlockExecutor(stateDB, log.TestingLogger(), proxyApp.Consensus(),
-		mock.Mempool{}, sm.MockEvidencePool{})
+		mock.Mempool{}, evmock.NewDefaultEvidencePool())
 
 	block := makeBlock(state, 1)
 	blockID := types.BlockID{Hash: block.Hash(), PartsHeader: block.MakePartSet(testPartSize).Header()}
@@ -334,7 +335,7 @@ func TestEndBlockValidatorUpdates(t *testing.T) {
 		log.TestingLogger(),
 		proxyApp.Consensus(),
 		mock.Mempool{},
-		sm.MockEvidencePool{},
+		evmock.NewDefaultEvidencePool(),
 	)
 
 	eventBus := types.NewEventBus()
@@ -401,7 +402,7 @@ func TestEndBlockValidatorUpdatesResultingInEmptySet(t *testing.T) {
 		log.TestingLogger(),
 		proxyApp.Consensus(),
 		mock.Mempool{},
-		sm.MockEvidencePool{},
+		evmock.NewDefaultEvidencePool(),
 	)
 
 	block := makeBlock(state, 1)
diff --git a/state/helpers_test.go b/state/helpers_test.go
index a85e35748..2805af63c 100644
--- a/state/helpers_test.go
+++ b/state/helpers_test.go
@@ -22,14 +22,6 @@ type paramsChangeTestCase struct {
 	params types.ConsensusParams
 }
 
-// always returns true if asked if any evidence was already committed.
-type mockEvPoolAlwaysCommitted struct{}
-
-func (m mockEvPoolAlwaysCommitted) PendingEvidence(int64) []types.Evidence { return nil }
-func (m mockEvPoolAlwaysCommitted) AddEvidence(types.Evidence) error       { return nil }
-func (m mockEvPoolAlwaysCommitted) Update(*types.Block, sm.State)          {}
-func (m mockEvPoolAlwaysCommitted) IsCommitted(types.Evidence) bool        { return true }
-
 func newTestApp() proxy.AppConns {
 	app := &testApp{}
 	cc := proxy.NewLocalClientCreator(app)
diff --git a/state/services.go b/state/services.go
index a30956bdc..df6ce8f8f 100644
--- a/state/services.go
+++ b/state/services.go
@@ -43,12 +43,5 @@ type EvidencePool interface {
 	Update(*types.Block, State)
 	// IsCommitted indicates if this evidence was already marked committed in another block.
 	IsCommitted(types.Evidence) bool
+	IsPending(types.Evidence) bool
 }
-
-// MockEvidencePool is an empty implementation of EvidencePool, useful for testing.
-type MockEvidencePool struct{}
-
-func (m MockEvidencePool) PendingEvidence(int64) []types.Evidence { return nil }
-func (m MockEvidencePool) AddEvidence(types.Evidence) error       { return nil }
-func (m MockEvidencePool) Update(*types.Block, State)             {}
-func (m MockEvidencePool) IsCommitted(types.Evidence) bool        { return false }
diff --git a/state/validation.go b/state/validation.go
index 18608ab2c..c3231c270 100644
--- a/state/validation.go
+++ b/state/validation.go
@@ -132,12 +132,17 @@ func validateBlock(evidencePool EvidencePool, stateDB dbm.DB, state State, block
 
 	// Validate all evidence.
 	for _, ev := range block.Evidence.Evidence {
+		if evidencePool != nil {
+			if evidencePool.IsCommitted(ev) {
+				return types.NewErrEvidenceInvalid(ev, errors.New("evidence was already committed"))
+			}
+			if evidencePool.IsPending(ev) {
+				continue
+			}
+		}
 		if err := VerifyEvidence(stateDB, state, ev, &block.Header); err != nil {
 			return types.NewErrEvidenceInvalid(ev, err)
 		}
-		if evidencePool != nil && evidencePool.IsCommitted(ev) {
-			return types.NewErrEvidenceInvalid(ev, errors.New("evidence was already committed"))
-		}
 	}
 
 	// NOTE: We can't actually verify it's the right proposer because we dont
diff --git a/state/validation_test.go b/state/validation_test.go
index 10ff4c8ea..8cc7f44a7 100644
--- a/state/validation_test.go
+++ b/state/validation_test.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/tmhash"
+	evmock "github.com/tendermint/tendermint/evidence/mock"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/mock"
 	sm "github.com/tendermint/tendermint/state"
@@ -28,7 +29,7 @@ func TestValidateBlockHeader(t *testing.T) {
 		log.TestingLogger(),
 		proxyApp.Consensus(),
 		mock.Mempool{},
-		sm.MockEvidencePool{},
+		evmock.NewDefaultEvidencePool(),
 	)
 	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
 
@@ -98,7 +99,7 @@ func TestValidateBlockCommit(t *testing.T) {
 		log.TestingLogger(),
 		proxyApp.Consensus(),
 		mock.Mempool{},
-		sm.MockEvidencePool{},
+		evmock.NewDefaultEvidencePool(),
 	)
 	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
 	wrongSigsCommit := types.NewCommit(1, 0, types.BlockID{}, nil)
@@ -205,7 +206,7 @@ func TestValidateBlockEvidence(t *testing.T) {
 		log.TestingLogger(),
 		proxyApp.Consensus(),
 		mock.Mempool{},
-		sm.MockEvidencePool{},
+		evmock.NewDefaultEvidencePool(),
 	)
 	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
 
@@ -260,15 +261,70 @@ func TestValidateFailBlockOnCommittedEvidence(t *testing.T) {
 	var height int64 = 1
 	state, stateDB, _ := makeState(1, int(height))
 
-	blockExec := sm.NewBlockExecutor(stateDB, log.TestingLogger(), nil, nil, mockEvPoolAlwaysCommitted{})
+	evpool := evmock.NewDefaultEvidencePool()
+	blockExec := sm.NewBlockExecutor(
+		stateDB, log.TestingLogger(),
+		nil,
+		nil,
+		evpool)
 	// A block with a couple pieces of evidence passes.
 	block := makeBlock(state, height)
 	addr, _ := state.Validators.GetByIndex(0)
-	alreadyCommittedEvidence := types.NewMockEvidence(height, time.Now(), addr)
-	block.Evidence.Evidence = []types.Evidence{alreadyCommittedEvidence}
+	evpool.CommitEvidence(evpool.AddMockEvidence(height, addr))
+	block.Evidence.Evidence = evpool.CommittedEvidenceList
 	block.EvidenceHash = block.Evidence.Hash()
 	err := blockExec.ValidateBlock(state, block)
 
 	require.Error(t, err)
 	require.IsType(t, err, &types.ErrEvidenceInvalid{})
 }
+
+func TestValidateAlreadyPendingEvidence(t *testing.T) {
+	var height int64 = 1
+	state, stateDB, _ := makeState(2, int(height))
+
+	evpool := evmock.NewDefaultEvidencePool()
+	blockExec := sm.NewBlockExecutor(
+		stateDB, log.TestingLogger(),
+		nil,
+		nil,
+		evpool)
+	// A block with a couple pieces of evidence passes.
+	block := makeBlock(state, height)
+	addr, _ := state.Validators.GetByIndex(0)
+	addr2, _ := state.Validators.GetByIndex(0)
+	// add pending evidence
+	pendingEv := evpool.AddMockEvidence(height, addr)
+	// add evidence that hasn't seen before
+	ev := types.NewMockEvidence(height, time.Now(), addr2)
+	block.Evidence.Evidence = []types.Evidence{pendingEv, ev}
+	block.EvidenceHash = block.Evidence.Hash()
+	err := blockExec.ValidateBlock(state, block)
+
+	require.NoError(t, err)
+}
+
+// TODO: prevent committing duplicate votes
+//func TestValidateDuplicateEvidenceShouldFail(t *testing.T) {
+//	var height int64 = 1
+//	var evidence []types.Evidence
+//	state, stateDB, _ := makeState(1, int(height))
+//
+//	evpool := evmock.NewDefaultEvidencePool()
+//	blockExec := sm.NewBlockExecutor(
+//		stateDB, log.TestingLogger(),
+//		nil,
+//		nil,
+//		evpool)
+//	// A block with a couple pieces of evidence passes.
+//	block := makeBlock(state, height)
+//	addr, _ := state.Validators.GetByIndex(0)
+//	for i := 0; i < 2; i++ {
+//		evidence = append(evidence, types.NewMockEvidence(height, time.Now(), addr))
+//	}
+//	block.Evidence.Evidence = evidence
+//	block.EvidenceHash = block.Evidence.Hash()
+//	err := blockExec.ValidateBlock(state, block)
+//
+//	require.Error(t, err)
+//}