Using the CLEO-II data set we have searched for the decays B-0 --> D-(
+)D-(*-) We observe one candidate signal event for the decay B-0 -->
D+D*- with an expected background of 0.022 +/- 0.011 events. This yie
ld corresponds to a branching fraction of B(B-0 --> D+D*-) = [5.3(-3.
7)(+7.1)(stat)) +/- 1.0(syst)] X 10(-4) and an upper limit of B(B-0 --
> D-D*-) < 2.2 x 10(-3) at the 90% C.L. We see no significant excess
of signal above the expected background level in the other modes,,mode
s, and we calculate the 90% C.L. upper limits on the branching fractio
ns to be B(B-0 --> D+/-D-/+ < 1.8 X 10(-3) and B(B-0 --> D+D-) < 1.2
X 10(-3).