  The measurements of rare decays are highly sensitive to physics beyond the
standard model. In this article limits on the branching ratios of the decays
B0s -> mu+mu-, D0 -> mu+mu- and D+ -> pi+mu+mu- are presented. Furthermore the
first measurement of the branching fraction and CP asymmetry of Lambda_b -> p
pi- and Lambda_b -> p K- decays is described. Data samples with an integrated
luminosity of up to 2/fb collected at the Tevatron ppbar-collider at
sqrt(s)=1.96 TeV were used in these analyses. The results are consistent with
the standard model predictions and tighten the constraints on new physics
models.
