  We have searched for proton decays via p -> e^+ pi^0 and p -> mu^+ pi^0 using
data from a 91.7 kiloton year exposure of Super-Kamiokande-I and a 49.2 kiloton
year exposure of Super-Kamiokande-II. No candidate events were observed with
expected backgrounds induced by atmospheric neutrinos of 0.3 events for each
decay mode. From these results, we set lower limits on the partial lifetime of
8.2$\times10^{33}$ and 6.6$\times10^{33}$ years at 90% confidence level for p
-> e^+ pi^0 and p -> mu^+ pi^0 modes, respectively.
