diff --git a/etag.go b/etag.go
index f94c13b..93feb1c 100644
--- a/etag.go
+++ b/etag.go
@@ -67,7 +67,7 @@ func Handler(h http.Handler, weak bool) http.Handler {
 			return
 		}
 
-		etag := fmt.Sprintf("%v-%v", strconv.Itoa(hw.len),
+		etag := fmt.Sprintf("\"%v-%v\"", strconv.Itoa(hw.len),
 			hex.EncodeToString(hw.hash.Sum(nil)))
 
 		if weak {
diff --git a/etag_test.go b/etag_test.go
index 668a538..9f0b862 100644
--- a/etag_test.go
+++ b/etag_test.go
@@ -69,7 +69,7 @@ func (s EtagSuite) TestEtagExists() {
 	h := sha1.New()
 	h.Write(testStrBytes)
 
-	s.Equal(fmt.Sprintf("%v-%v", len(testStrBytes), hex.EncodeToString(h.Sum(nil))), res.Header.Get(headers.ETag))
+	s.Equal(fmt.Sprintf("\"%v-%v\"", len(testStrBytes), hex.EncodeToString(h.Sum(nil))), res.Header.Get(headers.ETag))
 }
 
 func (s EtagSuite) TestWeakEtagExists() {
@@ -81,7 +81,7 @@ func (s EtagSuite) TestWeakEtagExists() {
 	h := sha1.New()
 	h.Write(testStrBytes)
 
-	s.Equal(fmt.Sprintf("W/%v-%v", len(testStrBytes), hex.EncodeToString(h.Sum(nil))), res.Header.Get(headers.ETag))
+	s.Equal(fmt.Sprintf("W/\"%v-%v\"", len(testStrBytes), hex.EncodeToString(h.Sum(nil))), res.Header.Get(headers.ETag))
 }
 
 func (s EtagSuite) TestMatch() {