An adult female white-tailed trogon (Trogon viridis) was presented with abdominal enlargement and hard subcutaneous masses. Necropsy findings included bony masses extending from skeletal structures, disseminated pale foci in the liver, and a pale mass in the kidney. Histological examination revealed multifocal to coalescing granulomatous inflammation in the bone, liver, kidney, lung and spleen. Mycobacterium celatum was isolated from the liver and identified by DNA sequencing. This is the first report of M. celatum infection in an avian species.