diff --git a/vlib/builtin/builtin_test.v b/vlib/builtin/builtin_test.v
index 65b7bc27b9..7b069973f1 100644
--- a/vlib/builtin/builtin_test.v
+++ b/vlib/builtin/builtin_test.v
@@ -12,3 +12,9 @@ fn test_g_main_argv() {
 	}
 	assert first_arg.contains('builtin_test')
 }
+
+[if windows]
+fn test_bool_size() {
+	println(@LOCATION)
+	assert sizeof(C.BOOL) == 4
+}
diff --git a/vlib/builtin/builtin_windows.c.v b/vlib/builtin/builtin_windows.c.v
index 6f38acc72b..5f047ace42 100644
--- a/vlib/builtin/builtin_windows.c.v
+++ b/vlib/builtin/builtin_windows.c.v
@@ -7,7 +7,7 @@ module builtin
 // g_original_codepage - used to restore the original windows console code page when exiting
 __global g_original_codepage = u32(0)
 
-pub type C.BOOL = bool
+pub type C.BOOL = int
 
 pub type C.HINSTANCE = voidptr