Neurofibromatosis type 1 is the most common autosomal dominant inheritable disease, which is often associated with secondary forms of hypertension and with tumors of neuroectodermal origin. The authors present the results of evaluation of 60 members of 3 families. Of the 60 family members, 13 subjects had symptoms of neurofibromatosis type 1 disease, of which 7 subjects were evaluated. The case histories of patients are discussed: (1) An incidentally discovered adrenal tumor was proved to be a pheochromocytoma. (2) Because of complaints similar to thyrotoxicosis, thyrostatic drugs were administered for years without effect and, finally, an adrenal phaeochromocytoma was diagnosed after the presence of neurofibromatosis was established. (3) Preeclamptic pregnancy of a young primigravida complicated with severe HELLP syndrome (hemolysis-elevated liver enzymes-low platelet count) led to thorough evaluation which revealed renal artery stenosis. In this patient, percutaneous renal artery angioplasty resulted in a complete cessation of hypertension. (4) Glucocortocoid replacement therapy in a patient with neurofibromatosis type 1 resulted in a complete normalization of both secondary adrenal insufficiency and a previously unexplained iron-refractor iron-deficient anemia. The case histories of the patients demonstrate a lack of in-depth knowledge of neurofibromatosis in clinical practice. A regular follow-up of neurofibromatosis patients is suggested in specialized health centers.