  We analyze the numerical determination of the quark mixing factor V(us) from
hyperon semileptonic decays. The discrepancies between the results obtained in
two previous studies are clarified. Our fits indicate sizeable SU(3) breaking
corrections, which unfortunately can only be fully determined from the data at
the first order. The lack of a reliable theoretical calculation of second-order
symmetry breaking effects translates into a large systematic uncertainty, which
has not been taken into account previously. Our final result, V(us) = 0.226 +/-
0.005, is not competitive with the existing determinations from K(l3), K(l2)
and \tau decays.
