diff --git a/mempool/mempool_test.go b/mempool/mempool_test.go
index dc7d595a..d5f25396 100644
--- a/mempool/mempool_test.go
+++ b/mempool/mempool_test.go
@@ -6,6 +6,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io/ioutil"
+	mrand "math/rand"
 	"os"
 	"path/filepath"
 	"testing"
@@ -18,6 +19,7 @@ import (
 
 	"github.com/tendermint/tendermint/abci/example/counter"
 	"github.com/tendermint/tendermint/abci/example/kvstore"
+	abciserver "github.com/tendermint/tendermint/abci/server"
 	abci "github.com/tendermint/tendermint/abci/types"
 	cfg "github.com/tendermint/tendermint/config"
 	cmn "github.com/tendermint/tendermint/libs/common"
@@ -510,6 +512,54 @@ func TestMempoolTxsBytes(t *testing.T) {
 	assert.EqualValues(t, 0, mempool.TxsBytes())
 }
 
+// This will non-deterministically catch some concurrency failures like
+// https://github.com/tendermint/tendermint/issues/3509
+// TODO: all of the tests should probably also run using the remote proxy app
+// since otherwise we're not actually testing the concurrency of the mempool here!
+func TestMempoolRemoteAppConcurrency(t *testing.T) {
+	sockPath := fmt.Sprintf("unix:///tmp/echo_%v.sock", cmn.RandStr(6))
+	app := kvstore.NewKVStoreApplication()
+	cc, server := newRemoteApp(t, sockPath, app)
+	defer server.Stop()
+	config := cfg.ResetTestRoot("mempool_test")
+	mempool, cleanup := newMempoolWithAppAndConfig(cc, config)
+	defer cleanup()
+
+	// generate small number of txs
+	nTxs := 10
+	txLen := 200
+	txs := make([]types.Tx, nTxs)
+	for i := 0; i < nTxs; i++ {
+		txs[i] = cmn.RandBytes(txLen)
+	}
+
+	// simulate a group of peers sending them over and over
+	N := config.Mempool.Size
+	maxPeers := 5
+	for i := 0; i < N; i++ {
+		peerID := mrand.Intn(maxPeers)
+		txNum := mrand.Intn(nTxs)
+		tx := txs[int(txNum)]
+
+		// this will err with ErrTxInCache many times ...
+		mempool.CheckTxWithInfo(tx, nil, TxInfo{PeerID: uint16(peerID)})
+	}
+	err := mempool.FlushAppConn()
+	require.NoError(t, err)
+}
+
+// caller must close server
+func newRemoteApp(t *testing.T, addr string, app abci.Application) (clientCreator proxy.ClientCreator, server cmn.Service) {
+	clientCreator = proxy.NewRemoteClientCreator(addr, "socket", true)
+
+	// Start server
+	server = abciserver.NewSocketServer(addr, app)
+	server.SetLogger(log.TestingLogger().With("module", "abci-server"))
+	if err := server.Start(); err != nil {
+		t.Fatalf("Error starting socket server: %v", err.Error())
+	}
+	return clientCreator, server
+}
 func checksumIt(data []byte) string {
 	h := sha256.New()
 	h.Write(data)