Objective: To compare sublingual with vaginal misoprostol for the induction of tabor. Methods: This double-blind clinical trial randomized 150 women to receive every 6 h 25 mu g of sublingual misoprostol and vaginal placebo or 25 mu g of vaginal misoprostol and subtinguat placebo. Maternal and neonatal outcomes were analyzed and risk ratios (RRs) with 95% confidence intervals (Cls) calculated. The significance level was 5%. Results: Vaginal delivery rates were 57% in the subtingual group and 69% in the vaginal group (RR, 0.8; 95% Cl, 0.6-1.1). There were 11 cases of fetal distress in the subtinguat group and 4 cases in the vaginal group (RR, 2.7; 95% Cl, 0.9-8.2). There were no significant differences in the number of doses needed, interval between first dose and delivery, incidence of contractility disturbances, or neonatal results. Conclusion: The administration of misoprostol 25 mu g by the sublinguat route was neither more effective nor safer than the same dose administered vaginally. (c) 2006 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.9429195