An unusually high prevalence of uterine changes was observed on necropsy in a group of 169 female Seba's short-tailed bats (Carollia perspicillata). In this case study, 27 animals were affected from 1997 to 2007, representing 16% of the group population. All bats were of an indeterminate age and originated from the same facility, but were housed in three different zoological institutions. Deaths occurred year round. Most animals were found dead, with no previous clinical signs. Clinical signs, when present, included a markedly distended abdomen, extended periods of time perched on the exhibit floor, lethargy, and anorexia. Histologic changes included florid segmental to diffuse endometrial hyperplasia and occasional hemorrhage and adenomyosis. The cause for this condition has not been determined.