diff --git a/IPython/core/displayhook.py b/IPython/core/displayhook.py
index f1ae03f..9890b3d 100644
--- a/IPython/core/displayhook.py
+++ b/IPython/core/displayhook.py
@@ -244,8 +244,8 @@ class DisplayHook(Configurable):
 
     def flush(self):
         if not self.do_full_cache:
-            raise ValueError,"You shouldn't have reached the cache flush "\
-                  "if full caching is not enabled!"
+            raise ValueError("You shouldn't have reached the cache flush "
+                             "if full caching is not enabled!")
         # delete auto-generated vars from global namespace
 
         for n in range(1,self.prompt_count + 1):
diff --git a/IPython/core/interactiveshell.py b/IPython/core/interactiveshell.py
index 359f1c5..cf10a63 100644
--- a/IPython/core/interactiveshell.py
+++ b/IPython/core/interactiveshell.py
@@ -906,7 +906,7 @@ class InteractiveShell(SingletonConfigurable):
     def _set_call_pdb(self,val):
 
         if val not in (0,1,False,True):
-            raise ValueError,'new call_pdb value must be boolean'
+            raise ValueError('new call_pdb value must be boolean')
 
         # store value in instance
         self._call_pdb = val
diff --git a/IPython/core/logger.py b/IPython/core/logger.py
index 63fd765..d6eff7a 100644
--- a/IPython/core/logger.py
+++ b/IPython/core/logger.py
@@ -54,7 +54,7 @@ class Logger(object):
     # logmode is a validated property
     def _set_mode(self,mode):
         if mode not in ['append','backup','global','over','rotate']:
-            raise ValueError,'invalid log mode %s given' % mode
+            raise ValueError('invalid log mode %s given' % mode)
         self._logmode = mode
 
     def _get_mode(self):
@@ -131,8 +131,8 @@ class Logger(object):
         """Switch logging on/off. val should be ONLY a boolean."""
 
         if val not in [False,True,0,1]:
-            raise ValueError, \
-                  'Call switch_log ONLY with a boolean argument, not with:',val
+            raise ValueError('Call switch_log ONLY with a boolean argument, '
+                             'not with: %s' % val)
 
         label = {0:'OFF',1:'ON',False:'OFF',True:'ON'}
 
diff --git a/IPython/core/magic.py b/IPython/core/magic.py
index db52820..1be6d12 100644
--- a/IPython/core/magic.py
+++ b/IPython/core/magic.py
@@ -568,7 +568,7 @@ class Magics(object):
 
         mode = kw.get('mode','string')
         if mode not in ['string','list']:
-            raise ValueError,'incorrect mode given: %s' % mode
+            raise ValueError('incorrect mode given: %s' % mode)
         # Get options
         list_all = kw.get('list_all',0)
         posix = kw.get('posix', os.name == 'posix')
diff --git a/IPython/core/ultratb.py b/IPython/core/ultratb.py
index 72a46fd..49dfb0e 100644
--- a/IPython/core/ultratb.py
+++ b/IPython/core/ultratb.py
@@ -1103,8 +1103,8 @@ class FormattedTB(VerboseTB, ListTB):
                       len(self.valid_modes)
             self.mode = self.valid_modes[new_idx]
         elif mode not in self.valid_modes:
-            raise ValueError, 'Unrecognized mode in FormattedTB: <'+mode+'>\n'\
-                  'Valid modes: '+str(self.valid_modes)
+            raise ValueError('Unrecognized mode in FormattedTB: <'+mode+'>\n'
+                             'Valid modes: '+str(self.valid_modes))
         else:
             self.mode = mode
         # include variable details only in 'Verbose' mode
diff --git a/IPython/external/decorators/_decorators.py b/IPython/external/decorators/_decorators.py
index 75e2ee8..b87a455 100644
--- a/IPython/external/decorators/_decorators.py
+++ b/IPython/external/decorators/_decorators.py
@@ -217,7 +217,7 @@ def knownfailureif(fail_condition, msg=None):
         import nose
         def knownfailer(*args, **kwargs):
             if fail_val():
-                raise KnownFailureTest, msg
+                raise KnownFailureTest(msg)
             else:
                 return f(*args, **kwargs)
         return nose.tools.make_decorator(f)(knownfailer)
diff --git a/IPython/external/pexpect/_pexpect.py b/IPython/external/pexpect/_pexpect.py
index 0e6bfaa..3b8a4ea 100644
--- a/IPython/external/pexpect/_pexpect.py
+++ b/IPython/external/pexpect/_pexpect.py
@@ -608,11 +608,11 @@ class spawnb(object):
 
         parent_fd, child_fd = os.openpty()
         if parent_fd < 0 or child_fd < 0:
-            raise ExceptionPexpect, "Error! Could not open pty with os.openpty()."
+            raise ExceptionPexpect("Error! Could not open pty with os.openpty().")
 
         pid = os.fork()
         if pid < 0:
-            raise ExceptionPexpect, "Error! Failed os.fork()."
+            raise ExceptionPexpect("Error! Failed os.fork().")
         elif pid == 0:
             # Child.
             os.close(parent_fd)
@@ -655,7 +655,7 @@ class spawnb(object):
             fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY);
             if fd >= 0:
                 os.close(fd)
-                raise ExceptionPexpect, "Error! Failed to disconnect from controlling tty. It is still possible to open /dev/tty."
+                raise ExceptionPexpect("Error! Failed to disconnect from controlling tty. It is still possible to open /dev/tty.")
         except:
             # Good! We are disconnected from a controlling tty.
             pass
@@ -663,14 +663,14 @@ class spawnb(object):
         # Verify we can open child pty.
         fd = os.open(child_name, os.O_RDWR);
         if fd < 0:
-            raise ExceptionPexpect, "Error! Could not open child pty, " + child_name
+            raise ExceptionPexpect("Error! Could not open child pty, " + child_name)
         else:
             os.close(fd)
 
         # Verify we now have a controlling tty.
         fd = os.open("/dev/tty", os.O_WRONLY)
         if fd < 0:
-            raise ExceptionPexpect, "Error! Could not open controlling tty, /dev/tty"
+            raise ExceptionPexpect("Error! Could not open controlling tty, /dev/tty")
         else:
             os.close(fd)
 
diff --git a/IPython/lib/backgroundjobs.py b/IPython/lib/backgroundjobs.py
index 8b57bea..e14feed 100644
--- a/IPython/lib/backgroundjobs.py
+++ b/IPython/lib/backgroundjobs.py
@@ -375,8 +375,7 @@ class BackgroundJobBase(threading.Thread):
     stat_dead_c = -1
 
     def __init__(self):
-        raise NotImplementedError, \
-              "This class can not be instantiated directly."
+        raise NotImplementedError("This class can not be instantiated directly.")
 
     def _init(self):
         """Common initialization for all BackgroundJob objects"""
diff --git a/IPython/testing/tests/test_decorators.py b/IPython/testing/tests/test_decorators.py
index 5ce0a6b..9929b52 100644
--- a/IPython/testing/tests/test_decorators.py
+++ b/IPython/testing/tests/test_decorators.py
@@ -36,7 +36,7 @@ def getargspec(obj):
     elif inspect.ismethod(obj):
         func_obj = obj.im_func
     else:
-        raise TypeError, 'arg is not a Python function'
+        raise TypeError('arg is not a Python function')
     args, varargs, varkw = inspect.getargs(func_obj.func_code)
     return args, varargs, varkw, func_obj.func_defaults
 
diff --git a/IPython/utils/attic.py b/IPython/utils/attic.py
index 7b580a8..18d53b0 100644
--- a/IPython/utils/attic.py
+++ b/IPython/utils/attic.py
@@ -33,8 +33,8 @@ def mutex_opts(dict,ex_op):
     Call: mutex_opts(dict,[[op1a,op1b],[op2a,op2b]...]"""
     for op1,op2 in ex_op:
         if op1 in dict and op2 in dict:
-            raise ValueError,'\n*** ERROR in Arguments *** '\
-                  'Options '+op1+' and '+op2+' are mutually exclusive.'
+            raise ValueError('\n*** ERROR in Arguments *** '\
+                  'Options '+op1+' and '+op2+' are mutually exclusive.')
 
 
 class EvalDict:
diff --git a/IPython/utils/coloransi.py b/IPython/utils/coloransi.py
index 7997ff1..51267d6 100644
--- a/IPython/utils/coloransi.py
+++ b/IPython/utils/coloransi.py
@@ -145,7 +145,7 @@ class ColorSchemeTable(dict):
 
         if scheme_list:
             if default_scheme == '':
-                raise ValueError,'you must specify the default color scheme'
+                raise ValueError('you must specify the default color scheme')
             for scheme in scheme_list:
                 self.add_scheme(scheme)
             self.set_active_scheme(default_scheme)
@@ -157,7 +157,7 @@ class ColorSchemeTable(dict):
     def add_scheme(self,new_scheme):
         """Add a new color scheme to the table."""
         if not isinstance(new_scheme,ColorScheme):
-            raise ValueError,'ColorSchemeTable only accepts ColorScheme instances'
+            raise ValueError('ColorSchemeTable only accepts ColorScheme instances')
         self[new_scheme.name] = new_scheme
 
     def set_active_scheme(self,scheme,case_sensitive=0):
@@ -176,8 +176,8 @@ class ColorSchemeTable(dict):
         try:
             scheme_idx = valid_schemes.index(scheme_test)
         except ValueError:
-            raise ValueError,'Unrecognized color scheme: ' + scheme + \
-                  '\nValid schemes: '+str(scheme_names).replace("'', ",'')
+            raise ValueError('Unrecognized color scheme: ' + scheme + \
+                  '\nValid schemes: '+str(scheme_names).replace("'', ",''))
         else:
             active = scheme_names[scheme_idx]
             self.active_scheme_name = active
diff --git a/IPython/utils/path.py b/IPython/utils/path.py
index 2fed989..79cff4c 100644
--- a/IPython/utils/path.py
+++ b/IPython/utils/path.py
@@ -107,7 +107,7 @@ def get_py_filename(name, force_win32=None):
     if os.path.isfile(name):
         return name
     else:
-        raise IOError,'File `%r` not found.' % name
+        raise IOError('File `%r` not found.' % name)
 
 
 def filefind(filename, path_dirs=None):