diff --git a/Makefile.am b/Makefile.am
index 9a2b2502..7ce39765 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -18,6 +18,7 @@ SUBDIRS = bin src po
 
 check: test
 	pyflakes $(top_srcdir)
+	pep8 $(top_srcdir)
 
 test:
 	mkdir -p $(TESTS_TMPDIR)
diff --git a/src/sugar3/dispatch/__init__.py b/src/sugar3/dispatch/__init__.py
index 08fe25fa..872e2a16 100644
--- a/src/sugar3/dispatch/__init__.py
+++ b/src/sugar3/dispatch/__init__.py
@@ -1,6 +1,6 @@
 """Multi-consumer multi-producer dispatching mechanism
 
-Originally based on pydispatch (BSD) 
+Originally based on pydispatch (BSD)
 http://pypi.python.org/pypi/PyDispatcher/2.0.1
 See license.txt for original license.
 
diff --git a/src/sugar3/env.py b/src/sugar3/env.py
index 395d4128..419a0cbc 100644
--- a/src/sugar3/env.py
+++ b/src/sugar3/env.py
@@ -39,7 +39,7 @@ def get_profile_path(path=None):
         except OSError:
             print 'Could not create user directory.'
 
-    if path != None:
+    if path is not None:
         return os.path.join(base, path)
     else:
         return base
@@ -47,7 +47,7 @@ def get_profile_path(path=None):
 
 def get_logs_path(path=None):
     base = os.environ.get('SUGAR_LOGS_DIR', get_profile_path('logs'))
-    if path != None:
+    if path is not None:
         return os.path.join(base, path)
     else:
         return base
@@ -57,5 +57,6 @@ def get_user_activities_path():
     return os.environ.get("SUGAR_ACTIVITIES_PATH",
                           os.path.expanduser('~/Activities'))
 
+
 def get_user_library_path():
     return os.path.expanduser('~/Library')
diff --git a/src/sugar3/logger.py b/src/sugar3/logger.py
index bd7eaad8..783a07b8 100644
--- a/src/sugar3/logger.py
+++ b/src/sugar3/logger.py
@@ -72,7 +72,7 @@ def _except_hook(exctype, value, traceback):
     try:
         from IPython.ultraTB import AutoFormattedTB
         sys.excepthook = AutoFormattedTB(mode='Verbose',
-            color_scheme='NoColor')
+                                         color_scheme='NoColor')
     except ImportError:
         sys.excepthook = sys.__excepthook__
 
@@ -147,9 +147,10 @@ def start(log_filename=None):
                 if e.errno != errno.ENOSPC:
                     raise e
 
-    logging.basicConfig(level=logging.WARNING,
-            format="%(created)f %(levelname)s %(name)s: %(message)s",
-                        stream=SafeLogWrapper(sys.stderr))
+    logging.basicConfig(
+        level=logging.WARNING,
+        format="%(created)f %(levelname)s %(name)s: %(message)s",
+        stream=SafeLogWrapper(sys.stderr))
 
     if 'SUGAR_LOGGER_LEVEL' in os.environ:
         set_level(os.environ['SUGAR_LOGGER_LEVEL'])
@@ -177,7 +178,7 @@ class TraceRepr(repr_.Repr):
 
     # better handling of subclasses of basic types, e.g. for DBus
     _TYPES = [int, long, bool, tuple, list, array.array, set, frozenset,
-        collections.deque, dict, str]
+              collections.deque, dict, str]
 
     def repr1(self, x, level):
         for t in self._TYPES:
@@ -194,7 +195,7 @@ class TraceRepr(repr_.Repr):
 
 
 def trace(logger=None, logger_name=None, skip_args=None, skip_kwargs=None,
-    maxsize_list=30, maxsize_dict=30, maxsize_string=300):
+          maxsize_list=30, maxsize_dict=30, maxsize_string=300):
 
     if skip_args is None:
         skip_args = []
@@ -218,12 +219,12 @@ def trace(logger=None, logger_name=None, skip_args=None, skip_kwargs=None,
 
         params_formatted = ", ".join(
             [trace_repr.repr(a)
-                for (idx, a) in enumerate(args) if idx not in skip_args] + \
+                for (idx, a) in enumerate(args) if idx not in skip_args] +
             ['%s=%s' % (k, trace_repr.repr(v))
                 for (k, v) in kwargs.items() if k not in skip_kwargs])
 
         trace_logger.log(TRACE, "%s(%s) invoked", f.__name__,
-            params_formatted)
+                         params_formatted)
 
         try:
             res = f(*args, **kwargs)
@@ -232,7 +233,7 @@ def trace(logger=None, logger_name=None, skip_args=None, skip_kwargs=None,
             raise
 
         trace_logger.log(TRACE, "%s(%s) returned %s", f.__name__,
-            params_formatted, trace_repr.repr(res))
+                         params_formatted, trace_repr.repr(res))
 
         return res
 
diff --git a/src/sugar3/mime.py b/src/sugar3/mime.py
index a9046e7e..43cc0ecb 100644
--- a/src/sugar3/mime.py
+++ b/src/sugar3/mime.py
@@ -50,15 +50,15 @@ def _get_supported_image_mime_types():
 _extensions = {}
 _globs_timestamps = []
 _generic_types = [
-{
-    'id': GENERIC_TYPE_TEXT,
-    'name': _('Text'),
-    'icon': 'text-x-generic',
-    'types': [
+    {
+        'id': GENERIC_TYPE_TEXT,
+        'name': _('Text'),
+        'icon': 'text-x-generic',
+        'types': [
         'text/plain', 'text/rtf', 'application/pdf', 'application/x-pdf',
         'text/html', 'application/vnd.oasis.opendocument.text',
         'application/rtf', 'text/rtf', 'application/epub+zip'],
-},
+    },
 {
     'id': GENERIC_TYPE_IMAGE,
     'name': _('Image'),
diff --git a/src/sugar3/network.py b/src/sugar3/network.py
index bd1cd509..7e0ecef9 100644
--- a/src/sugar3/network.py
+++ b/src/sugar3/network.py
@@ -94,7 +94,7 @@ class ChunkedGlibHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
         self._file = None
         self._srcid = 0
         SimpleHTTPServer.SimpleHTTPRequestHandler.__init__(
-                                        self, request, client_address, server)
+            self, request, client_address, server)
 
     def log_request(self, code='-', size='-'):
         pass
@@ -188,11 +188,11 @@ class GlibURLDownloader(GObject.GObject):
 
     __gsignals__ = {
         'finished': (GObject.SignalFlags.RUN_FIRST, None,
-            ([GObject.TYPE_PYOBJECT, GObject.TYPE_PYOBJECT])),
+                     ([GObject.TYPE_PYOBJECT, GObject.TYPE_PYOBJECT])),
         'error': (GObject.SignalFlags.RUN_FIRST, None,
-            ([GObject.TYPE_PYOBJECT])),
+                  ([GObject.TYPE_PYOBJECT])),
         'progress': (GObject.SignalFlags.RUN_FIRST, None,
-            ([GObject.TYPE_PYOBJECT])),
+                     ([GObject.TYPE_PYOBJECT])),
     }
 
     CHUNK_SIZE = 4096
diff --git a/src/sugar3/profile.py b/src/sugar3/profile.py
index 7482da60..a77aef0a 100644
--- a/src/sugar3/profile.py
+++ b/src/sugar3/profile.py
@@ -73,9 +73,9 @@ class Profile(object):
         color = client.get_string('/desktop/sugar/user/color')
 
         return nick is not '' and \
-               color is not '' and \
-               self.pubkey is not None and \
-               self.privkey_hash is not None
+            color is not '' and \
+            self.pubkey is not None and \
+            self.privkey_hash is not None
 
     def _load_pubkey(self):
         key_path = os.path.join(env.get_profile_path(), 'owner.key.pub')
diff --git a/src/sugar3/util.py b/src/sugar3/util.py
index baec3b13..4a36e048 100644
--- a/src/sugar3/util.py
+++ b/src/sugar3/util.py
@@ -184,14 +184,14 @@ class LRU:
 
     def __iter__(self):
         cur = self.first
-        while cur != None:
+        while cur is not None:
             cur2 = cur.next
             yield cur.me[1]
             cur = cur2
 
     def iteritems(self):
         cur = self.first
-        while cur != None:
+        while cur is not None:
             cur2 = cur.next
             yield cur.me
             cur = cur2