We report a patient with Cushing's disease and primary hyperparathyroidism who subsequently developed medullary thyroid carcinoma (MTC) and bilateral phaeochromocytomas. Genetic testing for multiple endocrine neoplasia type 1 (MEN1) was negative, but a characteristic multiple endocrine neoplasia type 2A (MEN2A) RET-mutation was identified. Our case suggests that in patients with Cushing's disease who have other evidence of endocrine neoplasia, if MEN1 is excluded then MEN2 should be considered. © 2012 Blackwell Publishing Ltd.