diff --git a/api/stats/rtcstats_objects.h b/api/stats/rtcstats_objects.h
index b0cf3d0f65..a052c17383 100644
--- a/api/stats/rtcstats_objects.h
+++ b/api/stats/rtcstats_objects.h
@@ -361,7 +361,7 @@ class RTCInboundRTPStreamStats final : public RTCRTPStreamStats {
 
   RTCStatsMember<uint32_t> packets_received;
   RTCStatsMember<uint64_t> bytes_received;
-  RTCStatsMember<uint32_t> packets_lost;
+  RTCStatsMember<int32_t> packets_lost;  // Signed per RFC 3550
   // TODO(hbos): Collect and populate this value for both "audio" and "video",
   // currently not collected for "video". https://bugs.webrtc.org/7065
   RTCStatsMember<double> jitter;
diff --git a/pc/rtcstats_integrationtest.cc b/pc/rtcstats_integrationtest.cc
index b6c92f368f..158d54b41b 100644
--- a/pc/rtcstats_integrationtest.cc
+++ b/pc/rtcstats_integrationtest.cc
@@ -633,7 +633,9 @@ class RTCStatsReportVerifier {
     }
     verifier.TestMemberIsNonNegative<uint32_t>(inbound_stream.packets_received);
     verifier.TestMemberIsNonNegative<uint64_t>(inbound_stream.bytes_received);
-    verifier.TestMemberIsNonNegative<uint32_t>(inbound_stream.packets_lost);
+    // packets_lost is defined as signed, but this should never happen in
+    // this test. See RFC 3550.
+    verifier.TestMemberIsNonNegative<int32_t>(inbound_stream.packets_lost);
     if (inbound_stream.media_type.is_defined() &&
         *inbound_stream.media_type == "video") {
       verifier.TestMemberIsUndefined(inbound_stream.jitter);
diff --git a/pc/rtcstatscollector.cc b/pc/rtcstatscollector.cc
index aa901796bf..915aabf061 100644
--- a/pc/rtcstatscollector.cc
+++ b/pc/rtcstatscollector.cc
@@ -224,7 +224,7 @@ void SetInboundRTPStreamStatsFromMediaReceiverInfo(
   inbound_stats->bytes_received =
       static_cast<uint64_t>(media_receiver_info.bytes_rcvd);
   inbound_stats->packets_lost =
-      static_cast<uint32_t>(media_receiver_info.packets_lost);
+      static_cast<int32_t>(media_receiver_info.packets_lost);
   inbound_stats->fraction_lost =
       static_cast<double>(media_receiver_info.fraction_lost);
 }
diff --git a/pc/rtcstatscollector_unittest.cc b/pc/rtcstatscollector_unittest.cc
index 413b13b616..8047ddec7e 100644
--- a/pc/rtcstatscollector_unittest.cc
+++ b/pc/rtcstatscollector_unittest.cc
@@ -1817,7 +1817,7 @@ TEST_F(RTCStatsCollectorTest, CollectRTCInboundRTPStreamStats_Audio) {
   voice_media_info.receivers[0].local_stats.push_back(
       cricket::SsrcReceiverInfo());
   voice_media_info.receivers[0].local_stats[0].ssrc = 1;
-  voice_media_info.receivers[0].packets_lost = 42;
+  voice_media_info.receivers[0].packets_lost = -1;  // Signed per RFC3550
   voice_media_info.receivers[0].packets_rcvd = 2;
   voice_media_info.receivers[0].bytes_rcvd = 3;
   voice_media_info.receivers[0].codec_payload_type = 42;
@@ -1867,7 +1867,7 @@ TEST_F(RTCStatsCollectorTest, CollectRTCInboundRTPStreamStats_Audio) {
   expected_audio.codec_id = "RTCCodec_InboundAudio_42";
   expected_audio.packets_received = 2;
   expected_audio.bytes_received = 3;
-  expected_audio.packets_lost = 42;
+  expected_audio.packets_lost = -1;
   expected_audio.jitter = 4.5;
   expected_audio.fraction_lost = 5.5;