Hello, I got memory leak problem with QTimer (PyQt 4.3.1). Further, short example to detect problem. import sys from PyQt4 import QtCore, QtGui def schedule(): QtCore.QTimer.singleShot(0, schedule) def main( ): qApp = QtGui.QApplication(sys.argv) schedule() sys.exit(qApp.exec_()) main() -- Best regards, Artem Nikitin