A young woman presented with Cushing's syndrome. As a repeat surgical resection of a pituitary tumor did not cure her a bilateral adrenalectomy was performed, which resulted in symptomatic improvement of the patients condition. Several months later, a medullary carcinoma of the thyroid (MTC) was detected and resected. Retrospective analysis suggests that a paraneoplastic Cushing's syndrome may have been present in this patient. A connection of the pituitary tumor and the MTC could not be proved, a MEN-II-syndrome does not seem likely.