Measurement of Branching Ratios for K+/- -> pi+/- mu+ mu-
                     from the HyperCP at Fermilab.

 The HyperCP experiment is studying charged hyperon and kaon decays
 at Fermilab.  In two runs at Fermilab the experiment collected the
 largest sample of hyperon decays in the world as well as a large
 sample of charged-kaon decays.  Based on analysis of the 1997 data, I
 will present a preliminary result on the branching ratios of the
 K+ -> pi+ mu+ mu- and K- -> pi- mu+ mu- decays.  This is the first
 observation of the K- -> pi- mu+ mu- decay.