Two female adult Egyptian fruit bats (Rousettus aegyptiacus [bats 1 and 2]) from a colony of 25 to 30 bats at a zoological collection were evaluated because of abnormal behavior. The bats were found on the ground, appeared lethargic, had difficulty flying, and were cool to the touch. Prior to death, physical examinations performed by staff at the collection revealed no further obvious abnormalities. Both animals died within 48 hours of observation of the initial clinical signs. A male bat (bat 3) from the same group also died during the same 5-day period without premonitory clinical signs. All 3 bats underwent necropsy at the Department of Veterinary Medicine, University of Cambridge, England.