  We present constraints on the angle gamma of the Unitarity Triangle with a
Dalitz analysis of neutral D decays to K_Spi^+pi^- from the processes B^0 ->
barD^0 K^*0 (barB^0 -> D^0 barK^*0) and B0 -> D0 K*0 (barB^0 -> barD^0 barK^*0)
with K^*0 -> K^+pi^- (barK^*0 -> K^-pi^+). Using a sample of 371 10^6 BBbar
pairs collected with the Babar detector at PEP-II, we measure the angle gamma
as a function of r_S, the magnitude of the average ratio between b -> u and b
-> c amplitudes. Combining this result with the available information on r_S,
we obtain gamma = (162 +- 56) degrees or (342 +- 56) degrees and r_S<0.55 at
95% probability.
