Objective: To evaluate the efficacy, safety, and patient acceptability of sublingual misoprostol compared with an equivalent dose administered orally for labor induction at term. Study Design: One hundred women with medical or obstetric indications for induction of labor after 37 weeks of gestation and unfavorable cervices were randomized to receive 50 μg of misoprostol either orally or sublingually. The dose was repeated every 4 hours to a maximum of 5 doses if indicated. Previous cesarean delivery was a criteria for exclusion. Our primary outcome measure was the number of patients who went on to have a vaginal delivery within 24 hours of the induction. The need for oxytocin, mode of delivery, number of cesarean deliveries for fetal distress, uterine hyperstimulation rates, and neonatal outcomes were secondary outcome measures. Patient acceptability was assessed by questionnaires completed after delivery. Results: Significantly more patients were delivered of infants within 24 hours (73.8% versus 45.7%; relative risk, 1.6; 95% confidence interval, 1.1 to 2.4) and the induction to delivery intervals were significantly shorter (20 hours versus 28.3 hours; mean difference, 8.3 hours; 95% confidence interval, 1.2 to 15.4) in the sublingual group compared with the oral group. There was 1 case of uterine hyperstimulation in the sublingual group. There were no significant differences in the mode of delivery, interventions for fetal distress, or neonatal outcomes in the 2 groups. The satisfaction rates were 82.5% and 85.7% in the oral and sublingual groups respectively, and 9.5% of patients thought that the sublingual tablets did not dissolve completely. Conclusion: There has been no previous report in the literature of misoprostol given sublingually for labor induction. Sublingual misoprostol seems to have better efficacy than oral misoprostol, seems to be acceptable to patients, and is an option to be considered to induce labor at term. (Am J Obstet Gynecol 2002;186:72-6.)