diff --git a/codon/parser/visitors/typecheck/call.cpp b/codon/parser/visitors/typecheck/call.cpp
index ed43095f..0da5158e 100644
--- a/codon/parser/visitors/typecheck/call.cpp
+++ b/codon/parser/visitors/typecheck/call.cpp
@@ -844,6 +844,25 @@ ExprPtr TypecheckVisitor::transformHasAttr(CallExpr *expr) {
     }
   }
 
+  if (typ->getUnion()) {
+    ExprPtr cond = nullptr;
+    auto unionTypes = typ->getUnion()->getRealizationTypes();
+    int tag = -1;
+    for (size_t ui = 0; ui < unionTypes.size(); ui++) {
+      auto tu = realize(unionTypes[ui]);
+      if (!tu)
+        return nullptr;
+      auto te = N<IdExpr>(tu->getClass()->realizedTypeName());
+      auto e = N<BinaryExpr>(
+          N<CallExpr>(N<IdExpr>("isinstance"), expr->args[0].value, te), "&&",
+          N<CallExpr>(N<IdExpr>("hasattr"), te, N<StringExpr>(member)));
+      cond = !cond ? e : N<BinaryExpr>(cond, "||", e);
+    }
+    if (!cond)
+      return transform(N<BoolExpr>(false));
+    return transform(cond);
+  }
+
   bool exists = !ctx->findMethod(typ->getClass().get(), member).empty() ||
                 ctx->findMember(typ->getClass(), member);
   if (exists && args.size() > 1)
diff --git a/test/parser/types.codon b/test/parser/types.codon
index 3852deb1..1efb0393 100644
--- a/test/parser/types.codon
+++ b/test/parser/types.codon
@@ -2030,3 +2030,30 @@ def correlate(a, b, mode = 'valid'):
         raise ValueError(f"mode must be one of 'valid', 'same', or 'full' (got {repr(mode)})")
     return xret
 print(correlate([1], [2], 'full'))  # 5z
+
+#%% union_hasattr,barebones
+class A:
+    def foo(self):
+        print('foo')
+    def bar(self):
+        print('bar')
+class B:
+    def foo(self):
+        print('foo')
+    def baz(self):
+        print('baz')
+
+a = A()
+print(hasattr(a, 'foo'), hasattr(a, 'bar'), hasattr(a, 'baz'))
+#: True True False
+b = B()
+print(hasattr(b, 'foo'), hasattr(b, 'bar'), hasattr(b, 'baz'))
+#: True False True
+
+c: Union[A, B] = A()
+print(hasattr(c, 'foo'), hasattr(c, 'bar'), hasattr(c, 'baz'))
+#: True True False
+
+c = B()
+print(hasattr(c, 'foo'), hasattr(c, 'bar'), hasattr(c, 'baz'))
+#: True False True