diff --git a/src/components/main/css/select.rs b/src/components/main/css/select.rs
index e65c76c6e25..10ac49875d5 100644
--- a/src/components/main/css/select.rs
+++ b/src/components/main/css/select.rs
@@ -3,12 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use style::{Stylesheet, Stylist, UserAgentOrigin, with_errors_silenced};
+use extra::url;
 
 
 pub fn new_stylist() -> Stylist {
     let mut stylist = Stylist::new();
-    let ua_stylesheet = with_errors_silenced(
-        || Stylesheet::from_bytes(include_bin!("user-agent.css"), None, None));
+    let ua_stylesheet = with_errors_silenced(|| Stylesheet::from_bytes(
+        include_bin!("user-agent.css"),
+        url::from_str("chrome:///user-agent.css").unwrap(),
+        None,
+        None));
     stylist.add_stylesheet(ua_stylesheet, UserAgentOrigin);
     stylist
 }
diff --git a/src/components/script/html/cssparse.rs b/src/components/script/html/cssparse.rs
index 15532d76ab8..76d294e978e 100644
--- a/src/components/script/html/cssparse.rs
+++ b/src/components/script/html/cssparse.rs
@@ -48,10 +48,11 @@ pub fn spawn_css_parser(provenance: StylesheetProvenance,
                 let protocol_encoding_label = metadata.charset.as_ref().map(|s| s.as_slice());
                 let iter = ProgressMsgPortIterator { progress_port: progress_port };
                 Stylesheet::from_bytes_iter(
-                    iter, protocol_encoding_label, Some(environment_encoding))
+                    iter, metadata.final_url,
+                    protocol_encoding_label, Some(environment_encoding))
             }
-            InlineProvenance(_, data) => {
-                Stylesheet::from_str(data, environment_encoding)
+            InlineProvenance(base_url, data) => {
+                Stylesheet::from_str(data, base_url, environment_encoding)
             }
         };
         result_chan.send(sheet);
diff --git a/src/components/style/stylesheets.rs b/src/components/style/stylesheets.rs
index ab4ebb30a53..034f77a2f71 100644
--- a/src/components/style/stylesheets.rs
+++ b/src/components/style/stylesheets.rs
@@ -4,6 +4,7 @@
 
 use std::iter::Iterator;
 use std::ascii::StrAsciiExt;
+use extra::url::Url;
 
 use encoding::EncodingObj;
 
@@ -23,6 +24,7 @@ pub struct Stylesheet {
     rules: ~[CSSRule],
     namespaces: NamespaceMap,
     encoding: EncodingObj,
+    base_url: Url,
 }
 
 
@@ -40,25 +42,25 @@ pub struct StyleRule {
 
 impl Stylesheet {
     pub fn from_bytes_iter<I: Iterator<~[u8]>>(
-            mut input: I, protocol_encoding_label: Option<&str>,
+            mut input: I, base_url: Url, protocol_encoding_label: Option<&str>,
             environment_encoding: Option<EncodingObj>) -> Stylesheet {
         let mut bytes = ~[];
         // TODO: incremental decoding and tokinization/parsing
         for chunk in input {
             bytes.push_all(chunk)
         }
-        Stylesheet::from_bytes(bytes, protocol_encoding_label, environment_encoding)
+        Stylesheet::from_bytes(bytes, base_url, protocol_encoding_label, environment_encoding)
     }
 
     pub fn from_bytes(
-            bytes: &[u8], protocol_encoding_label: Option<&str>,
+            bytes: &[u8], base_url: Url, protocol_encoding_label: Option<&str>,
             environment_encoding: Option<EncodingObj>) -> Stylesheet {
         let (string, used_encoding) = decode_stylesheet_bytes(
             bytes, protocol_encoding_label, environment_encoding);
-        Stylesheet::from_str(string, used_encoding)
+        Stylesheet::from_str(string, base_url, used_encoding)
     }
 
-    pub fn from_str(css: &str, encoding: EncodingObj) -> Stylesheet {
+    pub fn from_str(css: &str, base_url: Url, encoding: EncodingObj) -> Stylesheet {
         static STATE_CHARSET: uint = 1;
         static STATE_IMPORTS: uint = 2;
         static STATE_NAMESPACES: uint = 3;
@@ -117,7 +119,7 @@ impl Stylesheet {
             }
             state = next_state;
         }
-        Stylesheet{ rules: rules, namespaces: namespaces, encoding: encoding }
+        Stylesheet{ rules: rules, namespaces: namespaces, encoding: encoding, base_url: base_url }
     }
 }