[en] We report on a search for the decay K_L→π⁰νν(bar sign), carried out as a part of E799-II, a rare K_L decay experiment at Fermilab. Within the standard model, the K_L→π⁰νν(bar sign) decay is dominated by direct CP violating processes, and thus an observation of the decay implies confirmation of direct CP violation. No events were observed, and we set an upper limit for the branching ratio of K_L→π⁰νν(bar sign) to be < 5.9 x10^-7 at the 90% confidence level. (c) 2000 The American Physical Society