A 14‐year‐old domestic shorthair cat was presented with hypoglycaemia and seizures of several weeks duration. Bloodwork revealed hypoglycaemia (1·83 mmol/l; reference range 4·22‐8·05 mmol/l) with concurrent normal insulin levels (171 pmol/l; reference range 72‐583 pmol/l). An insulinoma was suspected and medical and dietary management were attempted with minimal success. An exploratory laparotomy was performed and a single, well‐defined mass was found within the left lobe of the pancreas. The mass was removed and histologically classified as an islet cell carcinoma, consistent with an insulinoma. The cat had an episode of presumed postoperative pancreatitits, but recovered with appropriate treatment. The cat has had no clinical signs of recurrence of greater than 32 months postsurgery. There are only four cases of insulinoma in cats reported in the literature. All prior insulionomas reported were in older cats and were malignant in character, which is similar to the reports in the dog. This case is unique because of the apparent lack of local recurrence and development of metastatic disease, leading to the prolonged survival.