Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For Xi decay to Lambda pi followed by Lambda to p pi, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters alXi alLam. The asymmetry A_Xi Lambda, proportional to the difference of alXi alLam of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the Hyper CP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the asymmetry is AXiLam = [ -7 pm 12(rm stat) pm 6.2(rm sys) ] times 10-4, an order of magnitude better than the present limit.

Non-conservation of CP symmetry can manifest itself in non-lepton ichyperon decays as a difference in the decay parameter between the strange-baryon decay and its charge conjugate. By comparing the decay distribution in the $\Lambda$ helicity frame for the decay sequence $\Xi- \to \Lambda \pi-$,$\Lambda \to p \pi-$with that of $\overline Xi+$ decay, E756 at Fermilab did not observe any CP-odd effect at the $10-2$ level. The status of a follow-up experiment, HyperCP (FNAL E871), to search for CP violation in charged $\Xi-\Lambda$ decay with a sensitivity of $10-4$is also presented.