diff --git a/IPython/core/completerlib.py b/IPython/core/completerlib.py
index 98e4c6f..22e14d7 100644
--- a/IPython/core/completerlib.py
+++ b/IPython/core/completerlib.py
@@ -324,7 +324,7 @@ def cd_completer(self, event):
             return [compress_user(relpath, tilde_expand, tilde_val)]
 
         # if no completions so far, try bookmarks
-        bks = self.db.get('bookmarks',{}).iterkeys()
+        bks = self.db.get('bookmarks',{})
         bkmatches = [s for s in bks if s.startswith(event.symbol)]
         if bkmatches:
             return bkmatches
diff --git a/IPython/kernel/zmq/ipkernel.py b/IPython/kernel/zmq/ipkernel.py
index 0d79815..2a71dcf 100755
--- a/IPython/kernel/zmq/ipkernel.py
+++ b/IPython/kernel/zmq/ipkernel.py
@@ -599,7 +599,7 @@ class Kernel(Configurable):
                 exec(code, shell.user_global_ns, shell.user_ns)
                 result = working.get(resultname)
             finally:
-                for key in ns.iterkeys():
+                for key in ns:
                     working.pop(key)
 
             result_buf = serialize_object(result,
diff --git a/IPython/kernel/zmq/serialize.py b/IPython/kernel/zmq/serialize.py
index 282b2c2..72729a1 100644
--- a/IPython/kernel/zmq/serialize.py
+++ b/IPython/kernel/zmq/serialize.py
@@ -91,7 +91,7 @@ def serialize_object(obj, buffer_threshold=MAX_BYTES, item_threshold=MAX_ITEMS):
             buffers.extend(_extract_buffers(c, buffer_threshold))
     elif istype(obj, dict) and len(obj) < item_threshold:
         cobj = {}
-        for k in sorted(obj.iterkeys()):
+        for k in sorted(obj):
             c = can(obj[k])
             buffers.extend(_extract_buffers(c, buffer_threshold))
             cobj[k] = c
@@ -129,7 +129,7 @@ def unserialize_object(buffers, g=None):
         newobj = uncan_sequence(canned, g)
     elif istype(canned, dict) and len(canned) < MAX_ITEMS:
         newobj = {}
-        for k in sorted(canned.iterkeys()):
+        for k in sorted(canned):
             c = canned[k]
             _restore_buffers(c, bufs)
             newobj[k] = uncan(c, g)
diff --git a/IPython/parallel/client/client.py b/IPython/parallel/client/client.py
index 91ab385..f7a2f14 100644
--- a/IPython/parallel/client/client.py
+++ b/IPython/parallel/client/client.py
@@ -195,21 +195,21 @@ class Metadata(dict):
 
     def __getattr__(self, key):
         """getattr aliased to getitem"""
-        if key in self.iterkeys():
+        if key in self:
             return self[key]
         else:
             raise AttributeError(key)
 
     def __setattr__(self, key, value):
         """setattr aliased to setitem, with strict"""
-        if key in self.iterkeys():
+        if key in self:
             self[key] = value
         else:
             raise AttributeError(key)
 
     def __setitem__(self, key, value):
         """strict static key enforcement"""
-        if key in self.iterkeys():
+        if key in self:
             dict.__setitem__(self, key, value)
         else:
             raise KeyError(key)
diff --git a/IPython/parallel/util.py b/IPython/parallel/util.py
index 274da72..5df28ec 100644
--- a/IPython/parallel/util.py
+++ b/IPython/parallel/util.py
@@ -59,7 +59,7 @@ class Namespace(dict):
     
     def __getattr__(self, key):
         """getattr aliased to getitem"""
-        if key in self.iterkeys():
+        if key in self:
             return self[key]
         else:
             raise NameError(key)
diff --git a/IPython/utils/jsonutil.py b/IPython/utils/jsonutil.py
index 6b2cc89..f81766b 100644
--- a/IPython/utils/jsonutil.py
+++ b/IPython/utils/jsonutil.py
@@ -43,7 +43,7 @@ ISO8601_PAT=re.compile(r"^(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+)Z?([\+\-]\d{
 def rekey(dikt):
     """Rekey a dict that has been forced to use str keys where there should be
     ints by json."""
-    for k in dikt.iterkeys():
+    for k in dikt:
         if isinstance(k, string_types):
             ik=fk=None
             try: