We present an observation and time-integrated rate measurement of the decay
D-0-->K(+)pi (-)pi (0) produced in 9 fb(-1) of e(+)e(-) collisions near th
e Y(4S) resonance. The signal is inconsistent with an upward fluctuation of
the background by 4.9 standard deviations. We measured the time-integrated
rate of D-0-->K(+)pi (-)pi (0) normalized to the rate of (D-0) over bar --
> K(+)pi (-)pi (0) to be 0.0043(-0.0010)(+0.0011) (stat) +/- 0.0007 (syst).