Phœochromocytomas have many pathological and clinical features of interest. The present case report concerns a patient with two tumours, one of which was present in the middle mediastinum. This is only the second time that such an occurrence has been reported. Only one of the tumours (that in the right adrenal gland) secreted adrenaline, and difficulty was experienced in localising the mediastinal tumour. It was found that direct adrenal venous sampling proved misleading for purposes of localisation