diff --git a/.travis.yml b/.travis.yml
index 948de48863ec36389337beb273d9599888f7c05a..0734177bc23476f24736bc4e27bb7e4cbd04fd5d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,6 +17,8 @@ install:
   # Build gflags
   # TODO(noetzli): Remove when gflags available through Travis
   - pushd /tmp/ && curl -L https://github.com/gflags/gflags/archive/v2.1.2.tar.gz -o gflags.tar.gz && tar xfz gflags.tar.gz && cd gflags-2.1.2 && cmake . && make && popd
+  # Download clang-format-diff.py to check source code formatting
+  - pushd /tmp/ && curl -L http://llvm.org/svn/llvm-project/cfe/trunk/tools/clang-format/clang-format-diff.py -o clang-format-diff.py && chmod +x clang-format-diff.py && popd
 
 before_script:
   # Add gflags to include/library paths
@@ -30,7 +32,7 @@ before_script:
 
 # Lousy hack to disable use and testing of fallocate, which doesn't behave quite
 # as EnvPosixTest::AllocateTest expects within the Travis OpenVZ environment.
-script: OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest
+script: OPT=-DTRAVIS CLANG_FORMAT_DIFF=/tmp/clang-format-diff.py make format && OPT=-DTRAVIS V=1 make -j4 check && OPT=-DTRAVIS V=1 make clean jclean rocksdbjava jtest
 
 notifications:
     email:
diff --git a/build_tools/format-diff.sh b/build_tools/format-diff.sh
index 2d60620091f98cac658b52714897b859f915de4e..5b2efdd1a9e7b09947a15862394d0968ebf04d7c 100755
--- a/build_tools/format-diff.sh
+++ b/build_tools/format-diff.sh
@@ -79,6 +79,12 @@ echo -e "Detect lines that doesn't follow the format rules:\r"
 echo "$diffs" | 
   sed -e "s/\(^-.*$\)/`echo -e \"$COLOR_RED\1$COLOR_END\"`/" |
   sed -e "s/\(^+.*$\)/`echo -e \"$COLOR_GREEN\1$COLOR_END\"`/"
+
+if [[ "$OPT" == *"-DTRAVIS"* ]]
+then
+  exit 1
+fi
+
 echo -e "Would you like to fix the format automatically (y/n): \c"
 
 # Make sure under any mode, we can read user input.