The most sensitive experiment to date to search for the muon and electron l
epton number violating decay K-L(0) --> mu(+/-)e(-/+) has detected no event
s consistent with this process. Based on this result, the 90% confidence le
vel upper limit on the branching fraction is B(K-L(0) +/- mu(+/-)e(-/+)) <
4.7 X 10(-12).