diff --git a/net/dcsctp/packet/chunk/init_ack_chunk.cc b/net/dcsctp/packet/chunk/init_ack_chunk.cc
index 14c126542f..c7ef9da1f1 100644
--- a/net/dcsctp/packet/chunk/init_ack_chunk.cc
+++ b/net/dcsctp/packet/chunk/init_ack_chunk.cc
@@ -80,7 +80,7 @@ void InitAckChunk::SerializeTo(std::vector<uint8_t>& out) const {
 }
 
 std::string InitAckChunk::ToString() const {
-  return rtc::StringFormat("INIT_ACK, initiate_tag=0x%0x, initial_tsn=%d",
+  return rtc::StringFormat("INIT_ACK, initiate_tag=0x%0x, initial_tsn=%u",
                            *initiate_tag(), *initial_tsn());
 }
 }  // namespace dcsctp
diff --git a/net/dcsctp/packet/chunk/init_chunk.cc b/net/dcsctp/packet/chunk/init_chunk.cc
index 5304350a46..8030107072 100644
--- a/net/dcsctp/packet/chunk/init_chunk.cc
+++ b/net/dcsctp/packet/chunk/init_chunk.cc
@@ -81,7 +81,7 @@ void InitChunk::SerializeTo(std::vector<uint8_t>& out) const {
 }
 
 std::string InitChunk::ToString() const {
-  return rtc::StringFormat("INIT, initiate_tag=0x%0x, initial_tsn=%d",
+  return rtc::StringFormat("INIT, initiate_tag=0x%0x, initial_tsn=%u",
                            *initiate_tag(), *initial_tsn());
 }