Midtrimester abortion was successfully induced in 55 of 60 patients with continuous extraovular infusion of prostaglandin F2alpha (PGF2alpha) following the insertion of intracervical laminaria tents. Intravenous oxytocin was also used in 38 (63%) of the 60 patients. The mean induction-abortion time (IAT) was 11.72 hours +/- 1.06 SD). Abortion was completed in 40% within 8 hours, 80% within 16 hours, and 93% within 24 hours. The mean total dose of PGF2alpha was 41.9 mg. There was no significant difference in IAT between the parous patients (13.40 hours +/- 1.90 SD) and the nulliparous patients (10.41 hours +/- 1.13 SD). There was no apparent correlation between IAT and the stages of gestation (12 to 22 weeks). The five patients who failed to abort within 24 to 36 hours underwent uterine evacuation, which was easily accomplished because there was a marked degree of cervical dilatation. Side effects and complications of the technique were few. Endometritis occurred in three patients, two of whom had had intrauterine devices in situ until just prior to the procedure. It appears that this method has a high success rate, an acceptable safety factor, good patient tolerance, and relatively few side effects.