A 10·5 year-old ♀ Pygmy slow loris Nycticebus pygmaeus at ZSL London Zoo was examined as part of a routine health check. Abdominal palpation revealed a discrete, mobile mass that appeared to be arising from the right ovary. The mass was surgically removed. Histopathological examination of the mass confirmed it to be a dysgerminoma. The loris showed no signs of recurrence or metastasis for the next 4 years, when it was euthanized for unrelated reasons. In human beings, metastasis is not infrequently associated with dysgerminomas but there is large variation in the incidence of metastasis among species. To the knowledge of the authors, this is the first reported case of dysgerminoma from a Pygmy slow loris, one of only four cases reported in any prosimian species, and is the first case in a prosimian with clinical follow-up.