diff --git a/pyqtgraph/widgets/SpinBox.py b/pyqtgraph/widgets/SpinBox.py
index ea59bf31..496ea37a 100644
--- a/pyqtgraph/widgets/SpinBox.py
+++ b/pyqtgraph/widgets/SpinBox.py
@@ -509,8 +509,14 @@ class SpinBox(QtGui.QAbstractSpinBox):
     def fixup(self, strn):
         # fixup is called when the spinbox loses focus with an invalid or intermediate string
         self.updateText()
-        strn.clear()
-        strn.append(self.lineEdit().text())
+
+        # support both PyQt APIs (for Python 2 and 3 respectively)
+        # http://pyqt.sourceforge.net/Docs/PyQt4/python_v3.html#qvalidator
+        try:
+            strn.clear()
+            strn.append(self.lineEdit().text())
+        except AttributeError:
+            return self.lineEdit().text()
 
     def interpret(self):
         """Return value of text or False if text is invalid."""