diff --git a/tests/unit/datepicker/core.js b/tests/unit/datepicker/core.js
index a8e394696f..485ce375ba 100644
--- a/tests/unit/datepicker/core.js
+++ b/tests/unit/datepicker/core.js
@@ -455,7 +455,7 @@ QUnit.test( "keystrokes", function( assert ) {
 } );
 
 QUnit.test( "mouse", function( assert ) {
-	assert.expect( 15 );
+	assert.expect( 16 );
 	var inl,
 		inp = testHelper.init( "#inp" ),
 		dp = $( "#ui-datepicker-div" ),
@@ -481,6 +481,13 @@ QUnit.test( "mouse", function( assert ) {
 	$( "button.ui-datepicker-close", dp ).simulate( "click", {} );
 	testHelper.equalsDate( assert, inp.datepicker( "getDate" ), new Date( 2008, 2 - 1, 4 ),
 		"Mouse click - abandoned" );
+	inp.datepicker( "hide" );
+
+	inp.val( "02/24/0999" ).datepicker( "show" );
+	$( ".ui-datepicker-calendar tbody a:contains(15)", dp ).simulate( "click", {} );
+	inp.datepicker( "show" );
+	testHelper.equalsDate( assert, inp.datepicker( "getDate" ), new Date( 999, 2 - 1, 15 ), "Mouse click inline - preset year 999" );
+	inp.datepicker( "hide" );
 
 	// Current/previous/next
 	inp.val( "02/04/2008" ).datepicker( "option", { showButtonPanel: true } ).datepicker( "show" );
diff --git a/tests/unit/datepicker/options.js b/tests/unit/datepicker/options.js
index 3055bc1997..39ba22f9e8 100644
--- a/tests/unit/datepicker/options.js
+++ b/tests/unit/datepicker/options.js
@@ -1124,7 +1124,7 @@ QUnit.test( "Ticket #7244: date parser does not fail when too many numbers are p
 } );
 
 QUnit.test( "formatDate", function( assert ) {
-	assert.expect( 16 );
+	assert.expect( 21 );
 	testHelper.init( "#inp" );
 	var gmtDate, fr, settings;
 	assert.equal( $.datepicker.formatDate( "d m y", new Date( 2001, 2 - 1, 3 ) ),
@@ -1164,6 +1164,14 @@ QUnit.test( "formatDate", function( assert ) {
 	assert.equal( $.datepicker.formatDate( "'jour' d 'de' MM (''DD''), yy",
 		new Date( 2001, 4 - 1, 9 ), settings ), "jour 9 de avril ('lundi'), 2001",
 		"Format date 'jour' d 'de' MM (''DD''), yy with settings" );
+
+	assert.equal( $.datepicker.formatDate( "yy-mm-dd", new Date( 100, 0, 1 ) ), "0100-01-01" );
+	assert.equal( $.datepicker.formatDate( "yy-mm-dd", new Date( 999, 0, 1 ) ), "0999-01-01" );
+	assert.equal( $.datepicker.formatDate( "yy-mm-dd", new Date( 1000, 0, 1 ) ), "1000-01-01" );
+
+	// -1 and 100000 will not be parsed correctly, but can be selected
+	assert.equal( $.datepicker.formatDate( "yy-mm-dd", new Date( -1, 0, 1 ) ), "-1-01-01" );
+	assert.equal( $.datepicker.formatDate( "yy-mm-dd", new Date( 10000, 0, 1 ) ), "10000-01-01" );
 } );
 
 // TODO: Fix this test so it isn't mysteriously flaky in Browserstack on certain OS/Browser combos
diff --git a/ui/widgets/datepicker.js b/ui/widgets/datepicker.js
index da70d5e00c..79b82b488f 100644
--- a/ui/widgets/datepicker.js
+++ b/ui/widgets/datepicker.js
@@ -1419,6 +1419,7 @@ $.extend( Datepicker.prototype, {
 			dayNames = ( settings ? settings.dayNames : null ) || this._defaults.dayNames,
 			monthNamesShort = ( settings ? settings.monthNamesShort : null ) || this._defaults.monthNamesShort,
 			monthNames = ( settings ? settings.monthNames : null ) || this._defaults.monthNames,
+			year,
 
 			// Check whether a format character is doubled
 			lookAhead = function( match ) {
@@ -1474,8 +1475,10 @@ $.extend( Datepicker.prototype, {
 							output += formatName( "M", date.getMonth(), monthNamesShort, monthNames );
 							break;
 						case "y":
-							output += ( lookAhead( "y" ) ? date.getFullYear() :
-								( date.getFullYear() % 100 < 10 ? "0" : "" ) + date.getFullYear() % 100 );
+							year = date.getFullYear();
+							output += ( lookAhead( "y" ) ?
+								( year >= 0 && year < 1000 ? ( year < 10 ? "000" : year < 100 ? "00" : "0" ) : "" ) + year :
+								( year % 100 < 10 ? "0" : "" ) + year % 100 );
 							break;
 						case "@":
 							output += date.getTime();