diff --git a/.github/workflows/compiler-test.yml b/.github/workflows/compiler-test.yml
index 425a948aec..32e9df4fa6 100644
--- a/.github/workflows/compiler-test.yml
+++ b/.github/workflows/compiler-test.yml
@@ -82,3 +82,11 @@ jobs:
         path: vg
     - name: Compile /vg/station Master
       run: main\bin\DMCompiler\DMCompiler.exe vg\vgstation13.dme --suppress-unimplemented
+    - name: Checkout CM Master
+      uses: actions/checkout@v2
+      with:
+        repository: cmss13-devs/cmss13
+        ref: master
+        path: cm
+    - name: Compile CM Master
+      run: main\bin\DMCompiler\DMCompiler.exe cm\colonialmarines.dme --suppress-unimplemented