A concentrated oxytocin infusion and prostaglandin E2 (PGE2) vaginal suppositories were compared in a retrospective analysis for indicated abortion in the mid-second trimester (17-24 weeks' gestation). Eighty-one women underwent second-trimester pregnancy termination, 59 by PGE2 suppositories and 22 by concentrated oxytocin infusion. Success was achieved by PGE2 in 93% (55 of 59) and oxytocin in 91% (20 of 22). The mean duration of labor was 13.1 hours with PGE2 and 8.2 hours with oxytocin. The mean dose of PGE2 was 65.2 mg; of oxytocin, 200 units. Women who received PGE2 experienced nausea (46%), vomiting (37%), fever (64%), and diarrhea (20%) despite appropriate premedication. Few side effects occurred in the women who were treated with oxytocin. We conclude that concentrated oxytocin infusion seems to be a reasonable alternative to PGE2 vaginal suppositories for induction of labor in the mid-second trimester.