Rabies virus was detected by fluorescent-antibody and mouse inoculation tests in the brain of one bat, Artibeus jamaicensis, collected at La Tante, Grenada on 19 June 1974. No rabies virus was found in the brains and/or salivary glands of 411 other Grenadian bats of 6 species tested, including 56 A. jamaicensis. Rabies neutralizing antibody was detected by the rapid fluorescent focus inhibition test (RFFIT) in 27 of 353 Grenadian bats. Positives occurred in each of the 6 species sampled, with 40.5% prevalence in A. jamaicensis. In 11 of 86 Trinidadian bats of 4 species known to carry rabies, positive sera occurred only in A. jamaicensis (18.6%) and A. lituratus (8.1%). The potential use of the RFFIT in determining rabies activity is discussed.