  We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context
of the Standard Model, the branching fractions for these decays are expected to
be highly suppressed, since they proceed through annhilation of the b and u-bar
quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B
Bbar decays collected with the BaBar detector at SLAC. We find no evidence for
these decays, and we set 90% confidence level upper limits on the branching
fractions BF(B- --> Ds- Phi) < 1.8x10^(-6) BF(B- --> Ds*- Phi) < 1.1x10^(-5).
These results are consistent with Standard Model expectations.
