  The CLEO collaboration reported the observation of the ``wrong sign'' decay
D0 -> K+ pi- in 1993. Recent upgrades to the CLEO detector, including the
installation of a silicon vertex detector, have increased the sensitivity of
the detector to D0 -> K+ pi-. Using 5.6 fb-1 of data we report a preliminary
measurement of the rate of the wrong sign decay D0 -> K+ pi-, to be BR(D0 -> K+
pi-)/BR(D0 -> K- pi+) = (0.31 +/- 0.09 +/- 0.07)%. Additionally, combining this
measurement with D0 proper lifetime information we set a limit on D0 - D0bar
mixing of BR(D0 -> D0bar -> K+ pi-)/BR(D0 -> K- pi+) < 1.1% @ 90% confidence
limit.
