src/pkg/http/fs.go      |  4 +++-
 src/pkg/http/fs_test.go | 17 ++++++++++++++++-

diff --git a/src/pkg/http/fs.go b/src/pkg/http/fs.go
index 17d5297b82c86614d849a7d9ef33b3a8b13b2c4e..28a0c51ef5b9c6d1fcd6bda042c7188df9e7d557 100644
--- a/src/pkg/http/fs.go
+++ b/src/pkg/http/fs.go
@@ -175,7 +175,9 @@ 		w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, d.Size))
 	}
 
 	w.Header().Set("Accept-Ranges", "bytes")
-	w.Header().Set("Content-Length", strconv.Itoa64(size))
+	if w.Header().Get("Content-Encoding") == "" {
+		w.Header().Set("Content-Length", strconv.Itoa64(size))
+	}
 
 	w.WriteHeader(code)
 
diff --git a/src/pkg/http/fs_test.go b/src/pkg/http/fs_test.go
index b94196258ee8dc1f204124abfa0a42365175ded9..554053449ecbd57cb9788f438a3c4984b6729a73 100644
--- a/src/pkg/http/fs_test.go
+++ b/src/pkg/http/fs_test.go
@@ -101,12 +101,27 @@ 		if err != nil {
 			t.Fatal(err)
 		}
 		if h := resp.Header.Get("Content-Type"); h != want {
-			t.Errorf("Content-Type mismatch: got %q, want %q", h, want)
+			t.Errorf("Content-Type mismatch: got %d, want %d", h, want)
 		}
 	}
 	get("text/plain; charset=utf-8")
 	override = true
 	get(ctype)
+}
+
+func TestServeFileWithContentEncoding(t *testing.T) {
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		w.Header().Set("Content-Encoding", "foo")
+		ServeFile(w, r, "testdata/file")
+	}))
+	defer ts.Close()
+	resp, err := Get(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if g, e := resp.ContentLength, int64(-1); g != e {
+		t.Errorf("Content-Length mismatch: got %q, want %q", g, e)
+	}
 }
 
 func getBody(t *testing.T, req Request) (*Response, []byte) {