diff --git a/tests/unit/datepicker/datepicker_options.js b/tests/unit/datepicker/datepicker_options.js
index 52ae74a74..3b69acf1a 100644
--- a/tests/unit/datepicker/datepicker_options.js
+++ b/tests/unit/datepicker/datepicker_options.js
@@ -41,7 +41,19 @@ test( "appendTo", function() {
 });
 
 test( "dateFormat", function() {
-	expect( 0 );
+	expect( 2 );
+	var input = $( "#datepicker" ).val( "1/1/2014" ).datepicker(),
+		picker = input.datepicker( "widget" ),
+		firstDayLink = picker.find( "td[id]:first a" ); 
+
+	input.datepicker( "open" );
+	firstDayLink.trigger( "mousedown" );
+	equal( input.val(), "1/1/2014", "default formatting" );
+
+	input.datepicker( "option", "dateFormat", "D" );
+	equal( input.val(), "Wednesday, January 01, 2014", "updated formatting" );
+
+	input.datepicker( "destroy" );
 });
 
 test( "eachDay", function() {
diff --git a/ui/datepicker.js b/ui/datepicker.js
index 3afe5afd0..abb18a44b 100644
--- a/ui/datepicker.js
+++ b/ui/datepicker.js
@@ -632,6 +632,13 @@ $.widget( "ui.datepicker", {
 			this.refresh();
 		}
 
+		if ( key === "dateFormat" ) {
+			this.date.setFormat( this.options.dateFormat );
+			if ( !this.inline ) {
+				this.element.val( this.date.format() );
+			}
+		}
+
 		if ( key === "showWeek" ) {
 			this.refresh();
 		}