diff --git a/CHANGELOG b/CHANGELOG
index ccf7b6a..4514274 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+* Fix an issue where Element#getStyle('height') returns null if the height is set to "auto." (kangax, jddalton)
+
 * Add unit tests for Element#descendantOf. (jddalton)
 
 * Form#serializeElements should not serialize file inputs. (kangax, Lonesome Boy)
diff --git a/src/dom.js b/src/dom.js
index d5df211..df0162b 100644
--- a/src/dom.js
+++ b/src/dom.js
@@ -387,7 +387,7 @@ Element.Methods = {
     element = $(element);
     style = style == 'float' ? 'cssFloat' : style.camelize();
     var value = element.style[style];
-    if (!value) {
+    if (!value || value == 'auto') {
       var css = document.defaultView.getComputedStyle(element, null);
       value = css ? css[style] : null;
     }
diff --git a/test/unit/dom_test.js b/test/unit/dom_test.js
index 4776924..6aedb61 100644
--- a/test/unit/dom_test.js
+++ b/test/unit/dom_test.js
@@ -891,6 +891,10 @@ new Test.Unit.Runner({
       this.assertEqual("14px", $('style_test_dimensions').getStyle('width'));
       this.assertEqual("17px", $('style_test_dimensions').getStyle('height'));
     }
+    
+    // height/width could always be calculated if it's set to "auto" (Firefox)
+    this.assertNotNull($('auto_dimensions').getStyle('height'));
+    this.assertNotNull($('auto_dimensions').getStyle('width'));
   },
   
   testElementGetOpacity: function() {
diff --git a/test/unit/fixtures/dom.html b/test/unit/fixtures/dom.html
index a58a20d..61c70da 100644
--- a/test/unit/fixtures/dom.html
+++ b/test/unit/fixtures/dom.html
@@ -274,4 +274,5 @@
   <div id="anonymous_element_3"></div>
 </div>
 
-<div id='elementToViewportDimensions' style='display: none'></div>
\ No newline at end of file
+<div id='elementToViewportDimensions' style='display: none'></div>
+<div id="auto_dimensions" style="height:auto"></div>
\ No newline at end of file