diff --git a/mypyc/rt_subtype.py b/mypyc/rt_subtype.py
index f3fe1a442d22..004e56ed75bc 100644
--- a/mypyc/rt_subtype.py
+++ b/mypyc/rt_subtype.py
@@ -51,7 +51,7 @@ def visit_rinstance(self, left: RInstance) -> bool:
         return is_subtype(left, self.right)
 
     def visit_runion(self, left: RUnion) -> bool:
-        return is_subtype(left, self.right)
+        return not self.right.is_unboxed and is_subtype(left, self.right)
 
     def visit_rprimitive(self, left: RPrimitive) -> bool:
         if is_short_int_rprimitive(left) and is_int_rprimitive(self.right):
diff --git a/mypyc/test-data/run-bools.test b/mypyc/test-data/run-bools.test
index 522296592c54..6d4244286185 100644
--- a/mypyc/test-data/run-bools.test
+++ b/mypyc/test-data/run-bools.test
@@ -221,3 +221,9 @@ def test_mixed_comparisons_i64() -> None:
             assert neq_mixed_i64(n, x) == (n != int(x))
             assert lt_mixed_i64(x, n) == (int(x) < n)
             assert gt_mixed_i64(n, x) == (n > int(x))
+
+[case testBoolMixInt]
+y = False
+print((y or 0) and True)
+[out]
+0
\ No newline at end of file
diff --git a/mypyc/test/test_typeops.py b/mypyc/test/test_typeops.py
index f414edd1a2bb..0d9860d88ffe 100644
--- a/mypyc/test/test_typeops.py
+++ b/mypyc/test/test_typeops.py
@@ -54,6 +54,13 @@ def test_bool(self) -> None:
         assert not is_runtime_subtype(bool_rprimitive, bit_rprimitive)
         assert not is_runtime_subtype(bool_rprimitive, int_rprimitive)
 
+    def test_union(self) -> None:
+        bool_int_mix = RUnion([bool_rprimitive, int_rprimitive])
+        assert not is_runtime_subtype(bool_int_mix, short_int_rprimitive)
+        assert not is_runtime_subtype(bool_int_mix, int_rprimitive)
+        assert not is_runtime_subtype(short_int_rprimitive, bool_int_mix)
+        assert not is_runtime_subtype(int_rprimitive, bool_int_mix)
+
 
 class TestUnionSimplification(unittest.TestCase):
     def test_simple_type_result(self) -> None: