diff --git a/python/cosmotool/borg.py b/python/cosmotool/borg.py
index df10fae..a2a85d6 100644
--- a/python/cosmotool/borg.py
+++ b/python/cosmotool/borg.py
@@ -1,7 +1,7 @@
 ### 
 ### BORG code is from J. Jasche
 ###
-import StringIO
+import io
 import numpy as np
 from numpy import *
 import os.path
@@ -154,9 +154,9 @@ def get_grid_values(xx,data, ranges):
 def get_mean_density(fdir, smin, step):
     """ estimate ensemble mean
     """
-    print '-'*60
-    print 'Get 3D ensemble mean density field'
-    print '-'*60
+    print('-'*60)
+    print('Get 3D ensemble mean density field')
+    print('-'*60)
 
     fname0 = fdir + 'initial_density_'+str(0)+'.dat'
     fname1 = fdir + 'final_density_'+str(0)+'.dat'
@@ -208,9 +208,9 @@ def get_mean_density(fdir, smin, step):
 def get_mean_density_fdir(fdir,init,steps):
     """ estimate ensemble mean
     """
-    print '-'*60
-    print 'Get 3D ensemble mean density field'
-    print '-'*60
+    print('-'*60)
+    print('Get 3D ensemble mean density field')
+    print('-'*60)
 
     fname0,fname1=build_filelist(fdir)
     
diff --git a/python/cosmotool/cic.py b/python/cosmotool/cic.py
index ec463d8..5a3372a 100644
--- a/python/cosmotool/cic.py
+++ b/python/cosmotool/cic.py
@@ -4,7 +4,7 @@ import numpy as np
 
 def cicParticles(particles, L, N):
 
-    if type(N) not in [int,long]:
+    if type(N) not in [int,int]:
       raise TypeError("N must be a numeric type")
 
     def shifted(i, t):
@@ -14,7 +14,7 @@ def cicParticles(particles, L, N):
 
     i =[]
     r = []
-    for d in xrange(3):
+    for d in range(3):
         q = ne.evaluate('(p%L)*N/L', local_dict={'p':particles[d], 'L':L, 'N':N })
         o = np.empty(q.size, dtype=np.int64)
         o[:] = np.floor(q)
diff --git a/python/cosmotool/cl_cic.py b/python/cosmotool/cl_cic.py
index b53c96b..bf0ab4e 100644
--- a/python/cosmotool/cl_cic.py
+++ b/python/cosmotool/cl_cic.py
@@ -163,8 +163,8 @@ class CIC_CL(object):
         # 2 dimensions
         translator['ndim'] = ndim
         translator['centered'] = '1' if centered else '0'
-        looperVariables = ','.join(['id%d' % d for d in xrange(ndim)])
-        looperFor = '\n'.join(['for (int id{dim}=0; id{dim} < 2; id{dim}++) {{'.format(dim=d) for d in xrange(ndim)])
+        looperVariables = ','.join(['id%d' % d for d in range(ndim)])
+        looperFor = '\n'.join(['for (int id{dim}=0; id{dim} < 2; id{dim}++) {{'.format(dim=d) for d in range(ndim)])
         looperForEnd = '}' * ndim
         
         kern = pragmas + CIC_PREKERNEL.format(**translator) + (CIC_KERNEL % {'looperVariables': looperVariables, 'looperFor': looperFor, 'looperForEnd':looperForEnd})
diff --git a/python/cosmotool/grafic.py b/python/cosmotool/grafic.py
index 4ea6f9b..9310172 100644
--- a/python/cosmotool/grafic.py
+++ b/python/cosmotool/grafic.py
@@ -27,7 +27,7 @@ def readGrafic(filename):
         BoxSize = delta * Nx * h
         
         checkPoint = 4*Ny*Nz
-        for i in xrange(Nx):
+        for i in range(Nx):
             checkPoint = struct.unpack("I", f.read(4))[0]
             if checkPoint != 4*Ny*Nz:
               raise ValueError("Invalid unformatted access")
@@ -57,7 +57,7 @@ def writeGrafic(filename, field, BoxSize, scalefac, **cosmo):
                                           cosmo['omega_M_0'], cosmo['omega_lambda_0'], 100*cosmo['h'], checkPoint))
         checkPoint = 4*Ny*Nz
         field = field.reshape(field.shape, order='F')
-        for i in xrange(Nx):
+        for i in range(Nx):
             f.write(struct.pack("I", checkPoint))
             f.write(field[i].astype(np.float32).tostring())
             f.write(struct.pack("I", checkPoint))
@@ -73,7 +73,7 @@ def writeWhitePhase(filename, field):
         
         field = field.reshape(field.shape, order='F')
         checkPoint = struct.pack("I", 4*Nx*Ny)
-        for i in xrange(Nx):
+        for i in range(Nx):
             f.write(checkPoint)
             f.write(field[i].astype(np.float32).tostring())
             f.write(checkPoint)
@@ -87,7 +87,7 @@ def readWhitePhase(filename):
         
         checkPoint_ref = 4*Ny*Nz
         
-        for i in xrange(Nx):
+        for i in range(Nx):
             if struct.unpack("I", f.read(4))[0] != checkPoint_ref:
               raise ValueError("Invalid unformatted access")
               
diff --git a/python/cosmotool/timing.py b/python/cosmotool/timing.py
index c6977f1..cad8463 100644
--- a/python/cosmotool/timing.py
+++ b/python/cosmotool/timing.py
@@ -14,7 +14,7 @@ def time_block(name):
     yield
     te = time.time()
  
-    print ('%s %2.2f sec' %  (name, te-ts))
+    print('%s %2.2f sec' %  (name, te-ts))
 
 def timeit(method):
     """This decorator add a timing request for each call to the decorated function.
@@ -28,7 +28,7 @@ def timeit(method):
         result = method(*args, **kw)
         te = time.time()
 
-        print ('%r (%r, %r) %2.2f sec' % (method.__name__, args, kw, te-ts))
+        print('%r (%r, %r) %2.2f sec' % (method.__name__, args, kw, te-ts))
         return result
 
     return timed
@@ -46,7 +46,7 @@ def timeit_quiet(method):
         result = method(*args, **kw)
         te = time.time()
 
-        print ('%r %2.2f sec' % (method.__name__, te-ts))
+        print('%r %2.2f sec' % (method.__name__, te-ts))
         return result
 
     return timed