diff --git a/Modules/_ctypes/libffi_osx/ffi.c b/Modules/_ctypes/libffi_osx/ffi.c
index 96826b5c8e5..1776b795e2f 100644
--- a/Modules/_ctypes/libffi_osx/ffi.c
+++ b/Modules/_ctypes/libffi_osx/ffi.c
@@ -102,7 +102,7 @@ initialize_aggregate(
 /* Perform machine independent ffi_cif preparation, then call
    machine dependent routine. */
 
-#if defined(X86_DARWIN)
+#if defined(X86_DARWIN) && !defined __x86_64__
 
 static inline bool
 struct_on_stack(
@@ -125,7 +125,7 @@ struct_on_stack(
 	}
 }
 
-#endif	// defined(X86_DARWIN)
+#endif	// defined(X86_DARWIN) && !defined __x86_64__
 
 // Arguments' ffi_type->alignment must be nonzero.
 ffi_status