A case of nonfunctioning suprasellar ectopic pituitary adenoma in a 49-year-old man is reported. The patient was refered to us with a partial visual field defect of the right eye. Neuroendocrinological examinations showed slightly higher levels of adrenocorticotrophic hormone and prolactin. MR imagings revealed an enhancing suprasellar tumor and a normal pituitary gland in the sella turcica. The patient underwent a craniotomy and the tumor was partially removed, although it was firmly attached to the pituitary stalk. The tumor was diagnosed histologically as a nonfunctioning pituitary adenoma. Cases of nonfunctioning suprasellar ectopic pituitary adenoma have rarely been reported. The pathophysiology of such tumors is discussed.