Hypotrichosis simplex is a descriptive term of hair loss without other ectodermal or systemic abnormalities. Hypotrichosis simplex with non-familial and generalized types has been seldom reported. A 30-year-old man visited our clinic complaining of scalp hair loss since birth. There was no hair on the arms, axillae and legs. He had relatively scanty eyebrows and pubic hairs. None of his family members had known health problems or any hereditary disease. Hair shaft examination based on electron microscopy did not reveal any structural abnormalities. Microscopic examination of a scalp biopsy specimen showed a reduced number of hair follicles with vellus hairs replacing terminal hairs. Herein we report a rare and interesting case of non-familial generalized hypotrichosis simplex. (Korean J Dermatol 2011;49(10):940∼942)