The authors report the cases of three brothers with pituitary adenomas who had classical findings of acromegaly and gigantism. Two had irreducibly elevated growth hormone (GH) values and underwent transsphenoidal microsurgical extirpation of their tumors. The third acromegalic brother had a normal GH value and evidence of panhypopituitarism; he had a small intrasellar tumor and a partially empty sella. The pattern of inheritance was probably autosomal recessive. A review of literature indicated that familial incidence of isolated acromegaly with pituitary adenomas is rare.