There was an impressive increase between 1965 and 1970 in the prevalence of contraceptive sterilization, an increase that accelerated in the later years of the period and was shared in by virtually all subgroups considered. Among couples in 1970 for whom sterilization had been an option (recognizing that it is a terminal method), about one of every five had chosen this method of contraception. About half of all sterilizations were vasectomies, though vasectomies have outnumbered tubal ligations in recent years. Differentials in prevalence and in increases during 1965–1970 are reported for a number of life-cycle and social variables. In addition, a profile of the contraceptive sterile is presented for recent sterilizations. Significant proportions are relatively young and of low parity at the time of sterilization. In the context of the continued diffusion of the pill and IUD and increases in legal abortion, the net demographic effect of increasing sterilization is regarded as low, though sterilization is an important component of an effective fertility control regime.