diff --git a/python/lammps.py b/python/lammps.py
index 64268bc345..f242ae1af6 100644
--- a/python/lammps.py
+++ b/python/lammps.py
@@ -340,7 +340,7 @@ class lammps(object):
         self.opened = 1
         comm_ptr = self.MPI._addressof(comm)
         comm_val = MPI_Comm.from_address(comm_ptr)
-        self.lmp = self.lib.lammps_open(narg,cargs,comm_val,None)
+        self.lmp = c_void_p(self.lib.lammps_open(narg,cargs,comm_val,None))
 
       else:
         if self.has_mpi4py and self.has_mpi_support:
@@ -355,10 +355,10 @@ class lammps(object):
           cargs = (c_char_p*narg)(*cmdargs)
           self.lib.lammps_open_no_mpi.argtypes = [c_int, c_char_p*narg, \
                                                   c_void_p]
-          self.lmp = self.lib.lammps_open_no_mpi(narg,cargs,None)
+          self.lmp = c_void_p(self.lib.lammps_open_no_mpi(narg,cargs,None))
         else:
           self.lib.lammps_open_no_mpi.argtypes = [c_int, c_char_p, c_void_p]
-          self.lmp = self.lib.lammps_open_no_mpi(0,None,None)
+          self.lmp = c_void_p(self.lib.lammps_open_no_mpi(0,None,None))
 
     else:
       # magic to convert ptr to ctypes ptr
diff --git a/unittest/python/python-numpy.py b/unittest/python/python-numpy.py
index 2d961d630c..67dee454a1 100644
--- a/unittest/python/python-numpy.py
+++ b/unittest/python/python-numpy.py
@@ -1,5 +1,6 @@
 import sys,os,unittest
 from lammps import lammps, LMP_STYLE_GLOBAL, LMP_STYLE_ATOM, LMP_TYPE_VECTOR, LMP_TYPE_SCALAR
+from ctypes import c_void_p
 
 class PythonNumpy(unittest.TestCase):
     def setUp(self):
@@ -11,6 +12,9 @@ class PythonNumpy(unittest.TestCase):
     def tearDown(self):
         del self.lmp
 
+    def testLammpsPointer(self):
+        self.assertEqual(type(self.lmp.lmp), c_void_p)
+
     def testExtractCompute(self):
         self.lmp.command("region       box block 0 2 0 2 0 2")
         self.lmp.command("create_box 1 box")