diff --git a/src/net/http/httputil/httputil.go b/src/net/http/httputil/httputil.go
index 2e523e9e26..09ea74d6d1 100644
--- a/src/net/http/httputil/httputil.go
+++ b/src/net/http/httputil/httputil.go
@@ -23,7 +23,9 @@ func NewChunkedReader(r io.Reader) io.Reader {
 
 // NewChunkedWriter returns a new chunkedWriter that translates writes into HTTP
 // "chunked" format before writing them to w. Closing the returned chunkedWriter
-// sends the final 0-length chunk that marks the end of the stream.
+// sends the final 0-length chunk that marks the end of the stream but does
+// not send the final CRLF that appears after trailers; trailers and the last
+// CRLF must be written separately.
 //
 // NewChunkedWriter is not needed by normal applications. The http
 // package adds chunking automatically if handlers don't set a
diff --git a/src/net/http/internal/chunked.go b/src/net/http/internal/chunked.go
index 63f321d03b..f06e5725f3 100644
--- a/src/net/http/internal/chunked.go
+++ b/src/net/http/internal/chunked.go
@@ -171,7 +171,9 @@ func removeChunkExtension(p []byte) ([]byte, error) {
 
 // NewChunkedWriter returns a new chunkedWriter that translates writes into HTTP
 // "chunked" format before writing them to w. Closing the returned chunkedWriter
-// sends the final 0-length chunk that marks the end of the stream.
+// sends the final 0-length chunk that marks the end of the stream but does
+// not send the final CRLF that appears after trailers; trailers and the last
+// CRLF must be written separately.
 //
 // NewChunkedWriter is not needed by normal applications. The http
 // package adds chunking automatically if handlers don't set a