diff --git a/Cargo.lock b/Cargo.lock
index 1ad6dcd35fe..df71f18de7d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -959,7 +959,6 @@ dependencies = [
  "heapsize_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "plugins 0.0.1",
  "range 0.0.1",
- "rustc-serialize 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 0.8.20 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/components/gfx_traits/Cargo.toml b/components/gfx_traits/Cargo.toml
index d0d913c1e5a..8ea8ca14f82 100644
--- a/components/gfx_traits/Cargo.toml
+++ b/components/gfx_traits/Cargo.toml
@@ -14,6 +14,5 @@ heapsize = "0.3.0"
 heapsize_derive = "0.1"
 plugins = {path = "../plugins"}
 range = {path = "../range"}
-rustc-serialize = "0.3"
 serde = "0.8"
 serde_derive = "0.8"
diff --git a/components/gfx_traits/lib.rs b/components/gfx_traits/lib.rs
index 1bb106ac23a..afc0aac0080 100644
--- a/components/gfx_traits/lib.rs
+++ b/components/gfx_traits/lib.rs
@@ -14,7 +14,6 @@ extern crate heapsize;
 #[macro_use] extern crate heapsize_derive;
 #[macro_use]
 extern crate range;
-extern crate rustc_serialize;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
@@ -41,7 +40,7 @@ const SPECIAL_STACKING_CONTEXT_ID_MASK: usize = 0xffff;
 /// One hardware pixel.
 ///
 /// This unit corresponds to the smallest addressable element of the display hardware.
-#[derive(Copy, Clone, RustcEncodable, Debug)]
+#[derive(Copy, Clone, Debug)]
 pub enum DevicePixel {}
 
 /// A newtype struct for denoting the age of messages; prevents race conditions.
@@ -172,7 +171,7 @@ impl FragmentType {
 }
 
 int_range_index! {
-    #[derive(Deserialize, Serialize, RustcEncodable)]
+    #[derive(Deserialize, Serialize)]
     #[doc = "An index that refers to a byte offset in a text run. This could \
              point to the middle of a glyph."]
     #[derive(HeapSizeOf)]