diff --git a/beacon-chain/blockchain/process_attestation.go b/beacon-chain/blockchain/process_attestation.go
index a2cd4acce1f2..258f661bd357 100644
--- a/beacon-chain/blockchain/process_attestation.go
+++ b/beacon-chain/blockchain/process_attestation.go
@@ -80,7 +80,7 @@ func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) ([]ui
 	}
 
 	// Verify beacon node has seen the target block before.
-	if !s.beaconDB.HasBlock(ctx, bytesutil.ToBytes32(tgt.Root)) {
+	if !s.hasBlock(ctx, bytesutil.ToBytes32(tgt.Root)) {
 		return nil, ErrTargetRootNotInDB
 	}
 
diff --git a/beacon-chain/blockchain/process_attestation_test.go b/beacon-chain/blockchain/process_attestation_test.go
index c43069e7f53b..181c1133db9b 100644
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
@@ -24,7 +25,7 @@ func TestStore_OnAttestation(t *testing.T) {
 	db := testDB.SetupDB(t)
 	defer testDB.TeardownDB(t, db)
 
-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: db, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
 	service, err := NewService(ctx, cfg)
 	if err != nil {
 		t.Fatal(err)
diff --git a/beacon-chain/blockchain/receive_attestation.go b/beacon-chain/blockchain/receive_attestation.go
index 587f77a06587..e41f732ca092 100644
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -74,7 +74,7 @@ func (s *Service) processAttestation() {
 			atts := s.attPool.ForkchoiceAttestations()
 			for _, a := range atts {
 				hasState := s.beaconDB.HasState(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot)) && s.beaconDB.HasState(ctx, bytesutil.ToBytes32(a.Data.Target.Root))
-				hasBlock := s.beaconDB.HasBlock(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
+				hasBlock := s.hasBlock(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
 				if !(hasState && hasBlock) {
 					continue
 				}
diff --git a/beacon-chain/blockchain/service.go b/beacon-chain/blockchain/service.go
index d0328ecf6f97..b06ac3366565 100644
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -434,3 +434,15 @@ func (s *Service) resumeForkChoice(justifiedCheckpoint *ethpb.Checkpoint, finali
 	store := protoarray.New(justifiedCheckpoint.Epoch, finalizedCheckpoint.Epoch, bytesutil.ToBytes32(finalizedCheckpoint.Root))
 	s.forkChoiceStore = store
 }
+
+// This returns true if block has been processed before. Two ways to verify the block has been processed:
+// 1.) Check fork choice store.
+// 2.) Check DB.
+// Checking 1.) is ten times faster than checking 2.)
+func (s *Service) hasBlock(ctx context.Context, root [32]byte) bool {
+	if s.forkChoiceStore.HasNode(root) {
+		return true
+	}
+
+	return s.beaconDB.HasBlock(ctx, root)
+}
diff --git a/beacon-chain/blockchain/service_test.go b/beacon-chain/blockchain/service_test.go
index 66825f68cac5..d5de66fd3508 100644
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -453,3 +453,75 @@ func TestChainService_PruneOldStates(t *testing.T) {
 		}
 	}
 }
+
+func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
+	ctx := context.Background()
+	db := testDB.SetupDB(t)
+	defer testDB.TeardownDB(t, db)
+	s := &Service{
+		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
+		finalizedCheckpt: &ethpb.Checkpoint{},
+		beaconDB:         db,
+	}
+	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
+	r, _ := ssz.HashTreeRoot(block.Block)
+	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{}}
+	state, _ := beaconstate.InitializeFromProto(bs)
+	if err := s.insertBlockToForkChoiceStore(ctx, block.Block, r, state); err != nil {
+		t.Fatal(err)
+	}
+
+	if s.hasBlock(ctx, [32]byte{}) {
+		t.Error("Should not have block")
+	}
+
+	if !s.hasBlock(ctx, r) {
+		t.Error("Should have block")
+	}
+}
+
+func BenchmarkHasBlockDB(b *testing.B) {
+	db := testDB.SetupDB(b)
+	defer testDB.TeardownDB(b, db)
+	ctx := context.Background()
+	s := &Service{
+		beaconDB: db,
+	}
+	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{}}
+	if err := s.beaconDB.SaveBlock(ctx, block); err != nil {
+		b.Fatal(err)
+	}
+	r, _ := ssz.HashTreeRoot(block.Block)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if !s.beaconDB.HasBlock(ctx, r) {
+			b.Fatal("Block is not in DB")
+		}
+	}
+}
+
+func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
+	ctx := context.Background()
+	db := testDB.SetupDB(b)
+	defer testDB.TeardownDB(b, db)
+	s := &Service{
+		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
+		finalizedCheckpt: &ethpb.Checkpoint{},
+		beaconDB:         db,
+	}
+	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
+	r, _ := ssz.HashTreeRoot(block.Block)
+	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{}}
+	state, _ := beaconstate.InitializeFromProto(bs)
+	if err := s.insertBlockToForkChoiceStore(ctx, block.Block, r, state); err != nil {
+		b.Fatal(err)
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if !s.forkChoiceStore.HasNode(r) {
+			b.Fatal("Block is not in fork choice store")
+		}
+	}
+}