diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1353,7 +1353,7 @@ def __init__(self, name, canvas, key, x=0, y=0, guiEvent=None):
 
 
 
-class FigureCanvasBase:
+class FigureCanvasBase(object):
     """
     The canvas the figure renders into.
 
@@ -2306,7 +2306,7 @@ class Cursors:  #namespace
 
 
 
-class NavigationToolbar2:
+class NavigationToolbar2(object):
     """
     Base class for the navigation cursor, version 2
 

diff --git a/lib/matplotlib/backends/backend_qt4.py b/lib/matplotlib/backends/backend_qt4.py
@@ -20,28 +20,9 @@
 except ImportError:
     figureoptions = None
 
-try:
-    from PyQt4 import QtCore, QtGui
-except ImportError:
-    raise ImportError("Qt4 backend requires that PyQt4 is installed.")
-
-import sip
-
-try :
-    if sip.getapi("QString") > 1 :
-        # Use new getSaveFileNameAndFilter()
-        _getSaveFileName = lambda self, msg, start, filters, selectedFilter : \
-                            QtGui.QFileDialog.getSaveFileNameAndFilter(self,  \
-                                msg, start, filters, selectedFilter)[0]
-    else :
-        # Use old getSaveFileName()
-        _getSaveFileName = QtGui.QFileDialog.getSaveFileName
-except (AttributeError, KeyError) :
-    # call to getapi() can fail in older versions of sip
-    # Use the old getSaveFileName()
-    _getSaveFileName = QtGui.QFileDialog.getSaveFileName
-
-backend_version = "0.9.1"
+from qt4_compat import QtCore, QtGui, _getSaveFileName, __version__
+
+backend_version = __version__
 def fn_name(): return sys._getframe(1).f_code.co_name
 
 DEBUG = False
@@ -292,22 +273,6 @@ def idle_draw(*args):
             self._idle = True
         if d: QtCore.QTimer.singleShot(0, idle_draw)
 
-
-# XXX Hackish fix: There's a bug in PyQt.  See this thread for details:
-# http://old.nabble.com/Qt4-backend:-critical-bug-with-PyQt4-v4.6%2B-td26205716.html
-# Once a release of Qt/PyQt is available without the bug, the version check
-# below can be tightened further to only be applied in the necessary versions.
-if QtCore.PYQT_VERSION_STR.startswith('4.6'):
-    class FigureWindow(QtGui.QMainWindow):
-       def __init__(self):
-           super(FigureWindow, self).__init__()
-       def closeEvent(self, event):
-           super(FigureWindow, self).closeEvent(event)
-           self.emit(QtCore.SIGNAL('destroyed()'))
-else:
-    FigureWindow = QtGui.QMainWindow
-# /end pyqt hackish bugfix
-
 class FigureManagerQT( FigureManagerBase ):
     """
     Public attributes
@@ -322,7 +287,7 @@ def __init__( self, canvas, num ):
         if DEBUG: print 'FigureManagerQT.%s' % fn_name()
         FigureManagerBase.__init__( self, canvas, num )
         self.canvas = canvas
-        self.window = FigureWindow()
+        self.window = QtGui.QMainWindow() 
         self.window.setAttribute(QtCore.Qt.WA_DeleteOnClose)
 
         self.window.setWindowTitle("Figure %d" % num)
@@ -341,7 +306,7 @@ def __init__( self, canvas, num ):
         if self.toolbar is not None:
             self.window.addToolBar(self.toolbar)
             QtCore.QObject.connect(self.toolbar, QtCore.SIGNAL("message"),
-                                   self.window.statusBar().showMessage)
+                                   self._show_message)
             tbs_height = self.toolbar.sizeHint().height()
         else:
             tbs_height = 0
@@ -366,6 +331,11 @@ def notify_axes_change( fig ):
                self.toolbar.update()
         self.canvas.figure.add_axobserver( notify_axes_change )
 
+    @QtCore.Slot()
+    def _show_message(self,s):
+        # Fixes a PySide segfault.
+        self.window.statusBar().showMessage(s)
+
     def _widgetclosed( self ):
         if self.window._destroying: return
         self.window._destroying = True

diff --git a/lib/matplotlib/backends/backend_qt4agg.py b/lib/matplotlib/backends/backend_qt4agg.py
@@ -91,7 +91,7 @@ def paintEvent( self, e ):
             else:
                 stringBuffer = self.renderer._renderer.tostring_argb()
 
-            qImage = QtGui.QImage(stringBuffer, self.renderer.width,
+            qImage = QtGui.QImage(stringBuffer, self.renderer.width, 
                                   self.renderer.height,
                                   QtGui.QImage.Format_ARGB32)
             p = QtGui.QPainter(self)

diff --git a/lib/matplotlib/backends/qt4_compat.py b/lib/matplotlib/backends/qt4_compat.py
@@ -0,0 +1,61 @@
+""" A Qt API selector that can be used to switch between PyQt and PySide.
+"""
+
+import os
+
+# Available APIs.
+QT_API_PYQT = 'pyqt'
+QT_API_PYSIDE = 'pyside'
+
+# Select PyQt4 or PySide using an environment variable, in the same way IPython does.
+# IPython is using PyQt as default (for now) so we will too.
+QT_API = os.environ.get('QT_API', QT_API_PYQT)
+
+if QT_API == QT_API_PYQT:
+    try:
+        from PyQt4 import QtCore, QtGui
+    except ImportError:
+        raise ImportError("Qt4 backend requires that PyQt4 is installed.")
+    # Alias PyQt-specific functions for PySide compatibility.
+    try:
+        QtCore.Slot = QtCore.pyqtSlot
+    except AttributeError:
+        QtCore.Slot = pyqtSignature # Not a perfect match but 
+                                    # works in simple cases
+    QtCore.Property = QtCore.pyqtProperty
+    __version__ = QtCore.PYQT_VERSION_STR
+    import sip
+    try :
+        if sip.getapi("QString") > 1 :
+            # Use new getSaveFileNameAndFilter()
+            _getSaveFileName = lambda self, msg, start, filters, \
+                                      selectedFilter : \
+                                QtGui.QFileDialog.getSaveFileNameAndFilter( \
+                                self, msg, start, filters, selectedFilter)[0]
+        else :
+            # Use old getSaveFileName()
+            _getSaveFileName = QtGui.QFileDialog.getSaveFileName
+    except (AttributeError, KeyError) :
+        # call to getapi() can fail in older versions of sip
+        # Use the old getSaveFileName()
+        _getSaveFileName = QtGui.QFileDialog.getSaveFileName
+
+elif QT_API == QT_API_PYSIDE:
+    try:
+        from PySide import QtCore, QtGui, __version__, __version_info__
+    except ImportError:
+        raise ImportError("Qt4 backend requires that PySide is installed.")
+    if __version_info__ < (1,0,3):
+        raise ImportError("Matplotlib backend_qt4 and backend_qt4agg require PySide >=1.0.3")
+
+    # Alias PySide-specific function for PyQt compatibilty
+    QtCore.pyqtProperty = QtCore.Property
+    QtCore.pyqtSignature = QtCore.Slot # Not a perfect match but 
+                                       # works in simple cases
+
+    _getSaveFileName = lambda self, msg, start, filters, selectedFilter : \
+                        QtGui.QFileDialog.getSaveFileName(self,  \
+                        msg, start, filters, selectedFilter)[0]
+else:
+    raise RuntimeError('Invalid Qt API %r, valid values are: %r or %r' %
+                       (QT_API, QT_API_PYQT, QT_API_PYSIDE))
diff --git a/lib/matplotlib/backends/qt4_editor/figureoptions.py b/lib/matplotlib/backends/qt4_editor/figureoptions.py
@@ -9,12 +9,12 @@
 import os.path as osp
 
 import matplotlib.backends.qt4_editor.formlayout as formlayout
-from PyQt4.QtGui import QIcon
+from matplotlib.backends.qt4_compat import QtGui
 
 def get_icon(name):
     import matplotlib
     basedir = osp.join(matplotlib.rcParams['datapath'], 'images')
-    return QIcon(osp.join(basedir, name))
+    return QtGui.QIcon(osp.join(basedir, name))
 
 LINESTYLES = {
               '-': 'Solid',