diff --git a/refl1d/garefl.py b/refl1d/garefl.py
index ef73749c..e584981e 100644
--- a/refl1d/garefl.py
+++ b/refl1d/garefl.py
@@ -32,6 +32,7 @@
 """
 __all__ = ["load"]
 
+import sys
 import os
 from os import getpid
 from ctypes import CDLL, c_int, c_double, c_void_p, c_char_p, byref
@@ -49,6 +50,13 @@
 from .profile import Microslabs
 from .material import SLD, Vacuum
 
+if sys.version_info[0] >= 3:
+    def tostr(s):
+        return s.decode('ascii')
+else:
+    def tostr(s):
+        return s
+
 def trace(fn):
     """simple function trace function"""
     return fn  # Comment this to turn on tracing
@@ -240,7 +248,7 @@ def _getdata(self, k, xs):
         if n == 0:
             return None
         data = empty((n, 4), 'd')
-        filename = self.dll.ex_get_data(self.models, k, xs, data.ctypes)
+        filename = tostr(self.dll.ex_get_data(self.models, k, xs, data.ctypes))
         Q, dQ, R, dR = data.T
         probe = QProbe(Q, dQ, data=(R, dR), name=filename)
         return probe
@@ -276,7 +284,7 @@ def output_model(self):
 
     @trace
     def par_names(self):
-        return [self.dll.ex_par_name(self.models, i)
+        return [tostr(self.dll.ex_par_name(self.models, i))
                 for i in range(self.num_pars)]
 
     @trace