A randomized, prospective study compared the safety and efficacy of hygroscopic cervical dilators (36 patients) with intracervical prostaglandin E2 (PGE2) gel (38 patients) in preinduction cervical ripening. Maternal age, gestational age and parity were similar in both groups. Both groups had similar cervical Bishop scores upon admission. The change in the cervical score was 3.0 +/- 0.3 (mean +/- SEM) in the dilator group and 2.8 +/- 0.4 in the PGE2 group (P = .7). The mean length of time from amniotomy to delivery was similar in both groups (10.1 +/- 1.0 and 10.3 +/- 1.3 hours, respectively) (P = .9). The proportions of patients in each arm of the study undergoing cesarean section were similar. Eight cesarean sections (21.0%) were performed in the PGE2 group; seven (19.4%) were performed in the dilator group (P = .9). Maternal morbidity, five-minute Apgar scores and admissions to the neonatal intensive care unit were similar in the two groups. Because patients were required to stay in the labor-and-delivery unit for four to six hours of fetal monitoring after PGE2 application, the costs were higher in that group. The dilators and PGE2 gel appear comparable in efficacy as preinduction cervical ripening agents. The need to monitor patients receiving PGE2 gel, however, appears to favor the choice of the dilators from a cost and convenience perspective.