The pathoetiology of chronic lymphocytic leukemia (CLL) in any species is not well understood. Despite lacking conclusive data on the etiology and clinical course of CLL, treatment can be successful. The diagnosis and treatment of CLL in a juvenile two-toed sloth (Choloepus didactylus) using data extrapolated from veterinary medicine and human medicine provides guidance for treatment of future cases of leukemia in other exotic animals.