This article describes the first series of patients to undergo gamete intrafallopian transfer (GIFT) as a treatment for infertility. Ten patients with the diagnosis of either unexplained infertility or male factor were treated with human menopausal gonadotropin and human chorionic gonadotropin before surgery by laparoscopy or minilaparotomy. Semen was collected 2.5 hours before oocyte pickup at surgery and treated by the technique of wash and swim-up. After gamete evaluation, one or two oocytes and 100,000 actively motile sperm were loaded into a catheter and introduced through the fimbria. The contents of the catheter were gently emptied at a site approximately 1.5 cm inside each fallopian tube. Patients received progesterone in oil, 12.5 mg/day, from day 4 after GIFT until up to 8 weeks of gestation. Four patients became pregnant: two pregnancies aborted; the other two pregnancies proceeded to the delivery of viable infants. GIFT may be considered as an alternative to in vitro fertilization in infertility cases in which at least one fallopian tube is patent.