diff --git a/pdbfixer/pdbfixer.py b/pdbfixer/pdbfixer.py
index 438e5dd..9fd7589 100644
--- a/pdbfixer/pdbfixer.py
+++ b/pdbfixer/pdbfixer.py
@@ -30,7 +30,7 @@
 """
 from __future__ import absolute_import
 __author__ = "Peter Eastman"
-__version__ = "1.5"
+__version__ = "1.6"
 
 import simtk.openmm as mm
 import simtk.openmm.app as app
diff --git a/setup.py b/setup.py
index fe7fc8c..cdf17ea 100644
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
 DOCLINES = __doc__.split("\n")
 
 ########################
-__version__ = '1.5'
+__version__ = '1.6'
 VERSION = __version__
 ISRELEASED = False
 ########################