To assess the risk for rabies transmission to humans by bats, we analyzed t
he prevalence of rabies in bats that encountered humans from 1977 to 1996 a
nd characterized the bat-human encounters. Rabies was diagnosed in 685 (15%
) of 4,470 bats tested. The prevalence of rabies in bats that bit humans wa
s 2.1 times higher than in bats that did not bite humans. At least a third
of the encounters were preventable.