diff --git a/gen_wrap.py b/gen_wrap.py
index 590c700551a201bab09b17e0741f03f31f612ad0..675b01f4eb90f47bc18d3e8429f4ed315113b08b 100644
--- a/gen_wrap.py
+++ b/gen_wrap.py
@@ -362,6 +362,10 @@ import six
 import sys
 import logging
 import threading
+import operator as _operator
+
+# isl has parameters called type which end up shadowing the built-in function.
+_type = type
 
 
 _PY3 = sys.version_info >= (3,)
@@ -1391,7 +1395,13 @@ def write_method_wrapper(gen, cls_name, meth):
                 pre_call("{val_name} = {name}._copy()".format(**fmt_args))
 
             pre_call("""
-                elif isinstance({name}, six.integer_types):
+                else:
+                    try:
+                        {name} = _operator.index({name})
+                    except TypeError:
+                        raise IslTypeError("{name} is a %s and cannot "
+                            "be cast to a Val" % _type({name}))
+
                     _cdata_{name} = lib.isl_val_int_from_si(
                         {arg0_name}._get_ctx_data(), {name})
 
@@ -1399,10 +1409,6 @@ def write_method_wrapper(gen, cls_name, meth):
                         raise Error("isl_val_int_from_si failed")
 
                     {val_name} = Val(_data=_cdata_{name})
-
-                else:
-                    raise IslTypeError("{name} is a %s and cannot "
-                        "be cast to a Val" % type({name}))
                 """
                 .format(**fmt_args))
 
diff --git a/test/test_isl.py b/test/test_isl.py
index 0fe13d35f6522d00ec97a889eb38bab9193098dd..9e18953878a8df2912404c45326678ab6ece074d 100644
--- a/test/test_isl.py
+++ b/test/test_isl.py
@@ -310,6 +310,16 @@ def test_align_spaces():
     assert result.get_var_dict() == m2.get_var_dict()
 
 
+def test_pass_numpy_int():
+    np = pytest.importorskip("numpy")
+
+    s = isl.BasicMap("{[i,j]: 0<=i,j<15}")
+    c0 = s.get_constraints()[0]
+
+    c1 = c0.set_constant_val(np.int32(5))
+    print(c1)
+
+
 if __name__ == "__main__":
     import sys
     if len(sys.argv) > 1: