  We analyse the constraints on dimension-six Delta F=1 effective operators in
models respecting the MFV hypothesis, both in the one-Higgs doublet case and in
the two-Higgs doublet scenario with large tan beta. The constraints are derived
mainly from the b -> s inclusive observables measured at the B factories. The
implications of these bounds in view of improved measurements in exclusive and
inclusive observables in b -> s l^+ l^- and s -> d nu nubar transitions are
discussed.
