diff --git a/pkg/core/blockchainer/blockchainer.go b/pkg/core/blockchainer/blockchainer.go
index 318ad2b72..dfbd4b39a 100644
--- a/pkg/core/blockchainer/blockchainer.go
+++ b/pkg/core/blockchainer/blockchainer.go
@@ -22,7 +22,6 @@ type Blockchainer interface {
 	AddHeaders(...*block.Header) error
 	AddBlock(*block.Block) error
 	AddStateRoot(r *state.MPTRoot) error
-	BlockHeight() uint32
 	CalculateClaimable(value *big.Int, startHeight, endHeight uint32) *big.Int
 	Close()
 	HeaderHeight() uint32
diff --git a/pkg/core/mempool/feer.go b/pkg/core/mempool/feer.go
index b2333f755..cc86de243 100644
--- a/pkg/core/mempool/feer.go
+++ b/pkg/core/mempool/feer.go
@@ -10,4 +10,5 @@ import (
 type Feer interface {
 	FeePerByte() int64
 	GetUtilityTokenBalance(util.Uint160) *big.Int
+	BlockHeight() uint32
 }
diff --git a/pkg/core/mempool/mem_pool.go b/pkg/core/mempool/mem_pool.go
index 883890c8f..060b7f3d6 100644
--- a/pkg/core/mempool/mem_pool.go
+++ b/pkg/core/mempool/mem_pool.go
@@ -5,7 +5,6 @@ import (
 	"math/big"
 	"sort"
 	"sync"
-	"time"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -30,8 +29,8 @@ var (
 
 // item represents a transaction in the the Memory pool.
 type item struct {
-	txn       *transaction.Transaction
-	timeStamp time.Time
+	txn        *transaction.Transaction
+	blockStamp uint32
 }
 
 // items is a slice of item.
@@ -148,8 +147,8 @@ func checkBalance(tx *transaction.Transaction, balance utilityBalanceAndFees) er
 // Add tries to add given transaction to the Pool.
 func (mp *Pool) Add(t *transaction.Transaction, fee Feer) error {
 	var pItem = item{
-		txn:       t,
-		timeStamp: time.Now().UTC(),
+		txn:        t,
+		blockStamp: fee.BlockHeight(),
 	}
 	mp.lock.Lock()
 	if mp.containsKey(t.Hash()) {
diff --git a/pkg/core/mempool/mem_pool_test.go b/pkg/core/mempool/mem_pool_test.go
index d297efbb4..e2a1f670c 100644
--- a/pkg/core/mempool/mem_pool_test.go
+++ b/pkg/core/mempool/mem_pool_test.go
@@ -23,6 +23,10 @@ func (fs *FeerStub) FeePerByte() int64 {
 	return fs.feePerByte
 }
 
+func (fs *FeerStub) BlockHeight() uint32 {
+	return 0
+}
+
 func (fs *FeerStub) GetUtilityTokenBalance(uint160 util.Uint160) *big.Int {
 	return balance
 }
diff --git a/pkg/rpc/server/server_helper_test.go b/pkg/rpc/server/server_helper_test.go
index 391fdf7da..d10b473ee 100644
--- a/pkg/rpc/server/server_helper_test.go
+++ b/pkg/rpc/server/server_helper_test.go
@@ -91,6 +91,10 @@ func (fs *FeerStub) FeePerByte() int64 {
 	return 0
 }
 
+func (fs *FeerStub) BlockHeight() uint32 {
+	return 0
+}
+
 func (fs *FeerStub) GetUtilityTokenBalance(acc util.Uint160) *big.Int {
 	return big.NewInt(1000000 * native.GASFactor)
 }