diff --git a/.travis.yml b/.travis.yml
index 767e521ca..1456726ba 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,7 +18,7 @@ before_script:
   - PREFIX=$TRAVIS_BUILD_DIR ./ci/build_harfbuzz.sh
 
 script:
-  - cargo fmt --all -- --write-mode=diff
+  - cargo fmt --all -- --check
   - cargo build --verbose --all
   - cargo test --verbose --all