A recent status and future prospect of nucleon decay experiments are summarized. The most stringent limits on proton decays are given by the largest water Cerenkov detector, Super-Kamiokande. A lower limit on the partial lifetime of a proton is set at 5.4 x 10(33) years for p --> e(+) pi(0) at 90% C.L., and 2.2 x 10(33) years for p --> vK(+). A next generation experiment with a megaton mass-scale detector can improve the sensitivities up to 1035 years for p --> epi(0) and 10(34) years for p --> vK(+). The detector is also suitable as a far detector of a long baseline neutrino oscillation experiment to search for CP violation.