diff --git a/src/net/http/client.go b/src/net/http/client.go
index 2cab53a585..5478690ecf 100644
--- a/src/net/http/client.go
+++ b/src/net/http/client.go
@@ -566,7 +566,8 @@ func urlErrorOp(method string) string {
 // connection to the server for a subsequent "keep-alive" request.
 //
 // The request Body, if non-nil, will be closed by the underlying
-// Transport, even on errors.
+// Transport, even on errors. The Body may be closed asynchronously after
+// Do returns.
 //
 // On error, any Response can be ignored. A non-nil Response with a
 // non-nil error only occurs when CheckRedirect fails, and even then
diff --git a/src/net/http/request.go b/src/net/http/request.go
index 0fb73c12b5..12039c9ae2 100644
--- a/src/net/http/request.go
+++ b/src/net/http/request.go
@@ -845,8 +845,9 @@ func NewRequest(method, url string, body io.Reader) (*Request, error) {
 // optional body.
 //
 // If the provided body is also an io.Closer, the returned
-// Request.Body is set to body and will be closed by the Client
-// methods Do, Post, and PostForm, and Transport.RoundTrip.
+// Request.Body is set to body and will be closed (possibly
+// asynchronously) by the Client methods Do, Post, and PostForm,
+// and Transport.RoundTrip.
 //
 // NewRequestWithContext returns a Request suitable for use with
 // Client.Do or Transport.RoundTrip. To create a request for use with