Seventeen pregnancies were reported from an international tubal sterilization data set comprising 1,862 minilaparotomy cases between 1978 and 1984. Of these 17, seven (41.2%) were diagnosed as luteal phase pregnancies. Of the 10 pregnancies due to sterilization failure, one was an ectopic pregnancy which occurred much later (20 months poststerilization) than the intrauterine pregnancies (10 months or less). Poststerilization pregnancy risk was greater among gravid women (those undergoing sterilization at the time of abortion or soon after childbirth) than among non-gravid women (those undergoing interval sterilization). These findings are, in general, consistent with those of previous studies using a much larger data set of primarily laparoscopic sterilizations. Pregnancies occurred with every type of mechanical tubal occlusion techniques included for study (the tubal ring, the Rocket Clip, the Secuclip and the Filshie Clip), and a frequently reported reason for failure was incorrect placement of the device. No pregnancies occurred in women sterilized with the non-mechanical Pomeroy/modified Pomeroy techniques. Findings of this analysis suggest that in minilaparotomy sterilization, for the mechanical tubal occlusion techniques to be as effective as the Pomeroy/modified Pomeroy techniques, more care and skill are required for the operator.