diff --git a/connection.go b/connection.go
index d906bb0..25e4ac2 100644
--- a/connection.go
+++ b/connection.go
@@ -208,9 +208,10 @@ type Connection struct {
 	nextStreamId     spdy.StreamId
 	receivedStreamId spdy.StreamId
 
-	pingIdLock sync.Mutex
-	pingId     uint32
-	pingChans  map[uint32]chan error
+	// pingLock protects pingChans and pingId
+	pingLock  sync.Mutex
+	pingId    uint32
+	pingChans map[uint32]chan error
 
 	shutdownLock sync.Mutex
 	shutdownChan chan error
@@ -274,16 +275,20 @@ func NewConnection(conn net.Conn, server bool) (*Connection, error) {
 // returns the response time
 func (s *Connection) Ping() (time.Duration, error) {
 	pid := s.pingId
-	s.pingIdLock.Lock()
+	s.pingLock.Lock()
 	if s.pingId > 0x7ffffffe {
 		s.pingId = s.pingId - 0x7ffffffe
 	} else {
 		s.pingId = s.pingId + 2
 	}
-	s.pingIdLock.Unlock()
 	pingChan := make(chan error)
 	s.pingChans[pid] = pingChan
-	defer delete(s.pingChans, pid)
+	s.pingLock.Unlock()
+	defer func() {
+		s.pingLock.Lock()
+		delete(s.pingChans, pid)
+		s.pingLock.Unlock()
+	}()
 
 	frame := &spdy.PingFrame{Id: pid}
 	startTime := time.Now()
@@ -612,10 +617,14 @@ func (s *Connection) handleDataFrame(frame *spdy.DataFrame) error {
 }
 
 func (s *Connection) handlePingFrame(frame *spdy.PingFrame) error {
-	if s.pingId&0x01 != frame.Id&0x01 {
+	s.pingLock.Lock()
+	pingId := s.pingId
+	pingChan, pingOk := s.pingChans[frame.Id]
+	s.pingLock.Unlock()
+
+	if pingId&0x01 != frame.Id&0x01 {
 		return s.framer.WriteFrame(frame)
 	}
-	pingChan, pingOk := s.pingChans[frame.Id]
 	if pingOk {
 		close(pingChan)
 	}