Neurofibromatosis type 1 is a phacomatosis. Neurofibromas are the most common tumours associated with the disease, and along with other tumours, make neurofibromatosis type 1 the most common tumour predisposing syndrome in humans. Hypertension may be coincidental, but at least two specific neurofibromatosis related causes must be considered, namely neurofibromatous involvement of the renal artery and pheochromocytoma. We have described the first known case of a patient with neurofibromatosis type 1 who developed hypertension due to an aldosterone-producing adenoma of the adrenal. The question of whether this association was coincidental or due to the tumour predisposition of neurofibromatosis type 1 was debated.