The development of puberty, the sexual debut and the sexual function were investigated in a longitudinal study of an unselected material of 220 primary cases of hypospadiacs, treated during the period 1965 to 1969 and followed-up during the period 1965 to 1974. The development of puberty in hypospadiacs strongly resembled that in a normal male population. Out of 121 hypospadiacs between 13 and 30 years of age 66 had had sexual intercourse. The median age for the sexual debut was 16.9 years compared to 16.6 years in a normal male population. Thirty out of 55 hypospadiacs without experience of sexual intercourse were in the age-group 13-16. Hypospadiacs with experience of sexual intercourse continued their sexual function was normal. Forty-one out of 66 were married and 24 out of 41 had children. In order to study the influence of the surgical treatment on the sexual debut and sexual function the 121 hypospadiacs were divided into two groups: those in whom treatment was completed before or at the age of 12 years, and those in whom treatment was completed at 13 years of age or later. The median age for the sexual debut was 15.5 years in the former group and 17.6 in the later group. An interesting finding was that almost half of the hypospadiacs in whom treatment was complted at 13 years of age or later had had a preoperative sexual debut despite the presence of curvature in all cases, and despite the fact that all types of hypospadias were represented. The median age for the sexual debut in this group was 17.1 years.