diff --git a/bchain/coins/blockchain.go b/bchain/coins/blockchain.go
index ba67d0a0..d1d1a530 100644
--- a/bchain/coins/blockchain.go
+++ b/bchain/coins/blockchain.go
@@ -151,7 +151,7 @@ func (c *blockChainWithMetrics) SendRawTransaction(tx string) (v string, err err
 	return c.b.SendRawTransaction(tx)
 }
 
-func (c *blockChainWithMetrics) ResyncMempool(onNewTxAddr func(txid string, addr string)) (err error) {
+func (c *blockChainWithMetrics) ResyncMempool(onNewTxAddr func(txid string, addr string)) (count int, err error) {
 	defer func(s time.Time) { c.observeRPCLatency("ResyncMempool", s, err) }(time.Now())
 	return c.b.ResyncMempool(onNewTxAddr)
 }
diff --git a/bchain/coins/btc/bitcoinrpc.go b/bchain/coins/btc/bitcoinrpc.go
index f928ed2d..ea4bf567 100644
--- a/bchain/coins/btc/bitcoinrpc.go
+++ b/bchain/coins/btc/bitcoinrpc.go
@@ -598,7 +598,8 @@ func (b *BitcoinRPC) GetTransaction(txid string) (*bchain.Tx, error) {
 
 // ResyncMempool gets mempool transactions and maps output scripts to transactions.
 // ResyncMempool is not reentrant, it should be called from a single thread.
-func (b *BitcoinRPC) ResyncMempool(onNewTxAddr func(txid string, addr string)) error {
+// It returns number of transactions in mempool
+func (b *BitcoinRPC) ResyncMempool(onNewTxAddr func(txid string, addr string)) (int, error) {
 	return b.Mempool.Resync(onNewTxAddr)
 }
 
diff --git a/bchain/coins/eth/ethrpc.go b/bchain/coins/eth/ethrpc.go
index dfe3b23b..1464ebca 100644
--- a/bchain/coins/eth/ethrpc.go
+++ b/bchain/coins/eth/ethrpc.go
@@ -496,7 +496,7 @@ func (b *EthereumRPC) SendRawTransaction(tx string) (string, error) {
 	return "", errors.New("SendRawTransaction: not implemented")
 }
 
-func (b *EthereumRPC) ResyncMempool(onNewTxAddr func(txid string, addr string)) error {
+func (b *EthereumRPC) ResyncMempool(onNewTxAddr func(txid string, addr string)) (int, error) {
 	return b.Mempool.Resync(onNewTxAddr)
 }
 
diff --git a/bchain/mempool_nonutxo.go b/bchain/mempool_nonutxo.go
index 0c1f14b7..8ccf018c 100644
--- a/bchain/mempool_nonutxo.go
+++ b/bchain/mempool_nonutxo.go
@@ -47,12 +47,12 @@ func (m *NonUTXOMempool) updateMappings(newTxToInputOutput map[string][]addrInde
 // Resync gets mempool transactions and maps outputs to transactions.
 // Resync is not reentrant, it should be called from a single thread.
 // Read operations (GetTransactions) are safe.
-func (m *NonUTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) error {
+func (m *NonUTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) (int, error) {
 	start := time.Now()
 	glog.V(1).Info("Mempool: resync")
 	txs, err := m.chain.GetMempool()
 	if err != nil {
-		return err
+		return 0, err
 	}
 	parser := m.chain.GetChainParser()
 	// allocate slightly larger capacity of the maps
@@ -102,5 +102,5 @@ func (m *NonUTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) erro
 	}
 	m.updateMappings(newTxToInputOutput, newAddrIDToTx)
 	glog.Info("Mempool: resync finished in ", time.Since(start), ", ", len(m.txToInputOutput), " transactions in mempool")
-	return nil
+	return len(m.txToInputOutput), nil
 }
diff --git a/bchain/mempool_utxo.go b/bchain/mempool_utxo.go
index e6233889..1963bc19 100644
--- a/bchain/mempool_utxo.go
+++ b/bchain/mempool_utxo.go
@@ -166,13 +166,13 @@ func (m *UTXOMempool) getTxAddrs(txid string, chanInput chan outpoint, chanResul
 // Resync gets mempool transactions and maps outputs to transactions.
 // Resync is not reentrant, it should be called from a single thread.
 // Read operations (GetTransactions) are safe.
-func (m *UTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) error {
+func (m *UTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) (int, error) {
 	start := time.Now()
 	glog.V(1).Info("mempool: resync")
 	m.onNewTxAddr = onNewTxAddr
 	txs, err := m.chain.GetMempool()
 	if err != nil {
-		return err
+		return 0, err
 	}
 	glog.V(2).Info("mempool: resync ", len(txs), " txs")
 	// allocate slightly larger capacity of the maps
@@ -215,5 +215,5 @@ func (m *UTXOMempool) Resync(onNewTxAddr func(txid string, addr string)) error {
 	m.updateMappings(newTxToInputOutput, newAddrIDToTx)
 	m.onNewTxAddr = nil
 	glog.Info("mempool: resync finished in ", time.Since(start), ", ", len(m.txToInputOutput), " transactions in mempool")
-	return nil
+	return len(m.txToInputOutput), nil
 }
diff --git a/bchain/types.go b/bchain/types.go
index 3edc214c..51e34656 100644
--- a/bchain/types.go
+++ b/bchain/types.go
@@ -135,7 +135,7 @@ type BlockChain interface {
 	EstimateFee(blocks int) (float64, error)
 	SendRawTransaction(tx string) (string, error)
 	// mempool
-	ResyncMempool(onNewTxAddr func(txid string, addr string)) error
+	ResyncMempool(onNewTxAddr func(txid string, addr string)) (int, error)
 	GetMempoolTransactions(address string) ([]string, error)
 	GetMempoolEntry(txid string) (*MempoolEntry, error)
 	// parser
diff --git a/blockbook.go b/blockbook.go
index 29ed983f..2e71f3f0 100644
--- a/blockbook.go
+++ b/blockbook.go
@@ -238,7 +238,7 @@ func main() {
 			glog.Error("resyncIndex ", err)
 			return
 		}
-		if err = chain.ResyncMempool(nil); err != nil {
+		if _, err = chain.ResyncMempool(nil); err != nil {
 			glog.Error("resyncMempool ", err)
 			return
 		}
@@ -385,10 +385,11 @@ func syncMempoolLoop() {
 	// resync mempool about every minute if there are no chanSyncMempool requests, with debounce 1 second
 	tickAndDebounce(resyncMempoolPeriodMs*time.Millisecond, debounceResyncMempoolMs*time.Millisecond, chanSyncMempool, func() {
 		internalState.StartedMempoolSync()
-		if err := chain.ResyncMempool(onNewTxAddr); err != nil {
+		if count, err := chain.ResyncMempool(onNewTxAddr); err != nil {
 			glog.Error("syncMempoolLoop ", errors.ErrorStack(err))
 		} else {
-			internalState.FinishedMempoolSync()
+			internalState.FinishedMempoolSync(count)
+
 		}
 	})
 	glog.Info("syncMempoolLoop stopped")
diff --git a/common/internalstate.go b/common/internalstate.go
index 7ff0836e..d5ca398e 100644
--- a/common/internalstate.go
+++ b/common/internalstate.go
@@ -38,6 +38,7 @@ type InternalState struct {
 	LastSync       time.Time `json:"lastSync"`
 
 	IsMempoolSynchronized bool      `json:"isMempoolSynchronized"`
+	MempoolSize           int       `json:"mempoolSize"`
 	LastMempoolSync       time.Time `json:"lastMempoolSync"`
 
 	DbColumns []InternalStateColumn `json:"dbColumns"`
@@ -81,10 +82,11 @@ func (is *InternalState) StartedMempoolSync() {
 }
 
 // FinishedMempoolSync marks end of mempool synchronization
-func (is *InternalState) FinishedMempoolSync() {
+func (is *InternalState) FinishedMempoolSync(mempoolSize int) {
 	is.mux.Lock()
 	defer is.mux.Unlock()
 	is.IsMempoolSynchronized = true
+	is.MempoolSize = mempoolSize
 	is.LastMempoolSync = time.Now()
 }