diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
index 747e9faa16..5027e738d4 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
@@ -275,7 +275,10 @@ int32_t RTPSender::DeRegisterSendPayload(
   return 0;
 }
 
-int8_t RTPSender::SendPayloadType() const { return payload_type_; }
+int8_t RTPSender::SendPayloadType() const {
+  CriticalSectionScoped cs(send_critsect_);
+  return payload_type_;
+}
 
 int RTPSender::SendPayloadFrequency() const {
   return audio_ != NULL ? audio_->AudioFrequency() : kVideoPayloadTypeFrequency;
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.h b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
index 665dbd7292..5cd21be609 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
@@ -344,7 +344,7 @@ class RTPSender : public RTPSenderInterface, public Bitrate::Observer {
   uint16_t target_send_bitrate_;
   uint16_t packet_over_head_;
 
-  int8_t payload_type_;
+  int8_t payload_type_ GUARDED_BY(send_critsect_);
   std::map<int8_t, ModuleRTPUtility::Payload *> payload_type_map_;
 
   RtpHeaderExtensionMap rtp_header_extension_map_;