Insulinomas in ferrets are one of the most common endocrinopathies treated by exotic companion mammal (ECM) veterinarians. This masterclass reviews endocrine pancreatic disorders in ECMs. Insulinomas in ferrets are discussed, but the emphasis is on less commonly encountered endocrine pancreatic disorders. Cases from the literature and the author’s personal experience are given as examples. Several cases of insulinomas in guinea pigs have been reported, and treatment with medications (diazoxide, corticosteroids) and surgery has been described. Insulinomas have been described in laboratory rats and a pancreatic islet cell adenoma has been reported in a pet rat. There is a case report of a rabbit with an insulinoma that was managed with prednisolone. The author had a case of insulinoma in a rabbit that was managed with diazoxide. Cataracts may be seen in rabbits with insulinomas. Diabetes mellitus is uncommon in ferrets and could be spontaneous or iatrogenic. Diabetes mellitus has been reported in degus, guinea pigs, and chinchillas. Hystricomorph insulin has a different structure from that of other mammals, making regulation challenging. Diabetes mellitus has also been described in Chinese and Djungarian hamsters. The author currently has a case of a Campbell’s dwarf hamster with diabetes mellitus that has been managed with insulin for almost one year. The author attempted to manage another diabetic dwarf hamster with an oral hypoglycemic without success. Laboratory rats are often used as a model for diabetes mellitus, and the author had a case of spontaneous diabetes mellitus in a pet rat.