diff --git a/client.go b/client.go
index 87ad3871..7c34cebb 100644
--- a/client.go
+++ b/client.go
@@ -224,7 +224,7 @@ func setHeaders(r *http.Request, n *Notification) {
 	if n.Priority > 0 {
 		r.Header.Set("apns-priority", strconv.Itoa(n.Priority))
 	}
-	if n.Expiration.After(time.Unix(0, 0)) {
+	if !n.Expiration.Before(time.Unix(0, 0)) {
 		r.Header.Set("apns-expiration", strconv.FormatInt(n.Expiration.Unix(), 10))
 	}
 	if n.PushType != "" {