diff --git a/feedlist.js b/feedlist.js
index 641bf69e7..a76e4a345 100644
--- a/feedlist.js
+++ b/feedlist.js
@@ -79,7 +79,7 @@ function viewfeed(feed, skip, subop, doc) {
 
 	var btnMarkAsRead = doc.getElementById("btnMarkFeedAsRead");
 
-	if (btnMarkAsRead && (feed < 0 || !isNumeric(feed))) {
+	if (btnMarkAsRead && !isNumeric(feed)) {
 		btnMarkAsRead.disabled = true;
 		btnMarkAsRead.className = "disabledButton";
 	}
diff --git a/tt-rss.js b/tt-rss.js
index a27e8dee5..d75157ae7 100644
--- a/tt-rss.js
+++ b/tt-rss.js
@@ -295,7 +295,7 @@ function viewfeed(feed, skip, subop) {
 
 	var btnMarkAsRead = document.getElementById("btnMarkFeedAsRead");
 
-	if (btnMarkAsRead && (feed < 0 || !isNumeric(feed))) {
+	if (btnMarkAsRead && !isNumeric(feed)) {
 		btnMarkAsRead.disabled = true;
 		btnMarkAsRead.className = "disabledButton";
 	}