We present a search for the "wrong-sign" decay D0 +-+- using 9 fb-1 of e+e- collisions on and just below the Y(4S) resonance. This decay can occur either through a doubly Cabibbo-suppressed process or through mixing to a D0 followed by a Cabibbo-favored process. Our result for the time-integrated wrong-sign rate relative to the decay D0 -+-+ is (0.0041-0.0011+0.0012(stat)0.0004(syst))(1.07 0.10)(phase space), which has a statistical significance of 3.9 standard deviations. 2001 The American Physical Society.