  We report results from a search for the decay Bs --> mu+ mu- using 1.3/fb of
pbar p collisions at sqrt(s)= 1.96 TeV collected by the D0 experiment at the
Fermilab Tevatron Collider. We find two candidate events, consistent with the
expected background of 1.24 +/- 0.99, and set an upper limit on the branching
fraction of B(Bs --> mu+ mu-) < 1.2e-7 at the 95% C.L.
