diff --git a/src/doc/src/guide/dependencies.md b/src/doc/src/guide/dependencies.md
index e199487f21e..fc16eb614c4 100644
--- a/src/doc/src/guide/dependencies.md
+++ b/src/doc/src/guide/dependencies.md
@@ -70,7 +70,7 @@ we choose to `cargo update`.
 
 You can now use the `regex` library using `extern crate` in `main.rs`.
 
-```
+```rust
 extern crate regex;
 
 use regex::Regex;