diff --git a/setup.py b/setup.py
index a0e59cf86..06555d4b0 100644
--- a/setup.py
+++ b/setup.py
@@ -171,7 +171,8 @@ def check_cudnn_version_and_warn(global_option: str, required_cudnn_version: int
     ext_modules.append(CppExtension("apex_C", ["csrc/flatten_unflatten.cpp"]))
 
 
-_, bare_metal_version = get_cuda_bare_metal_version(CUDA_HOME)
+if CUDA_HOME is not None:
+    _, bare_metal_version = get_cuda_bare_metal_version(CUDA_HOME)
 
 if has_flag("--distributed_adam", "APEX_DISTRIBUTED_ADAM"):
     if "--distributed_adam" in sys.argv: