One hundred and five wild-caught emerald tree boas (Corallus caninus) were added to a collection of 15 others, in Central Florida, during a 4-mo period. Eighty-one boas (67%) developed repetitive regurgitation during the 23-mo period after the initial introduction, and 61 (75%) of these died. Regurgitation occurred 3–4 days after feeding. Prevalence of regurgitation in this population of snakes was 25%/mo (range 0–42%), and incidence was 3.52/mo (range 0–13/mo). The cumulative mortality for those boas developing repetitive regurgitation (61 of 120) during the 23-mo epizootic was 51%. Hematologic findings included anemia and leukocytosis, with lymphocytosis, monocytosis, and azurophilia. Histologic evaluation of the gastrointestinal tract showed multifocal to diffuse lymphoplasmacytic inflammation with granuloma formation and positive immunohistochemical staining for chlamydial antigen. Electron microscopic evaluation of granulomas showed organisms consistent with Chlamydophila sp.