diff --git a/src/jquery.format.js b/src/jquery.format.js
index ca06ac4..cda8fbb 100644
--- a/src/jquery.format.js
+++ b/src/jquery.format.js
@@ -292,13 +292,15 @@
                         y = String(y + 1900);
                     }
                     
+                    var ordinals = { 1:  "st", 2:  "nd", 3:  "rd", 21: "st", 22: "nd", 23: "rd", 31: "st" };
                     var M = value.getMonth() + 1,
                         d = value.getDate(),
                         E = value.getDay(),
                         H = value.getHours(),
                         m = value.getMinutes(),
                         s = value.getSeconds(),
-                        S = value.getMilliseconds();
+                        S = value.getMilliseconds(),
+                        o = ordinals[d] || "th";
 
                     value = {
                         y: y,
@@ -313,9 +315,11 @@
                         EEE: _locale.date.daysShort[E],
                         EEEE: _locale.date.daysFull[E],
                         H: H,
-                        HH: formatNumber(H)
+                        HH: formatNumber(H),
+                        o: o,
+                        O: o.toUpperCase()
                     };
-                    
+
                     if (H === 0) {
                         value.h = 12;
                     } else if (H > 12) {
diff --git a/test/test.js b/test/test.js
index 265dae5..4267cd8 100644
--- a/test/test.js
+++ b/test/test.js
@@ -30,6 +30,46 @@ test("Basic requirements", function() {
     f = 'k:mm a';
     equals($.format.date(d, f), '12:00 PM');
     
+    d = new Date();
+    d.setDate(1);
+    f = 'do dO';
+    equals($.format.date(d, f), '1st 1ST');
+
+    d = new Date();
+    d.setDate(2);
+    f = 'do dO';
+    equals($.format.date(d, f), '2nd 2ND');
+
+    d = new Date();
+    d.setDate(3);
+    f = 'do dO';
+    equals($.format.date(d, f), '3rd 3RD');
+
+    d = new Date();
+    d.setDate(4);
+    f = 'do dO';
+    equals($.format.date(d, f), '4th 4TH');
+
+    d = new Date();
+    d.setDate(21);
+    f = 'do dO';
+    equals($.format.date(d, f), '21st 21ST');
+
+    d = new Date();
+    d.setDate(22);
+    f = 'do dO';
+    equals($.format.date(d, f), '22nd 22ND');
+
+    d = new Date();
+    d.setDate(23);
+    f = 'do dO';
+    equals($.format.date(d, f), '23rd 23RD');
+
+    d = new Date();
+    d.setDate(31);
+    f = 'do dO';
+    equals($.format.date(d, f), '31st 31ST');
+
     d = new Date();
     d.setFullYear(2012);
     d.setMonth(1);