Objective To compare the active management of term prelabour rupture of membranes with oral misoprostol with conservative management for 24 hours followed by induction with oxytocin or prostaglandin E 2 (PGE 2 ) gel. Design A non-blinded randomised controlled trial.Setting Induction and labour wards, Aberdeen Maternity Hospital.Population Sixty-one women with confirmed prelabour rupture of the membranes at ! 36 weeks of gestation.Methods The women were randomised to 50 Ag of oral misoprostol repeated every 4 hours, if required, to a maximum of five doses (active group), or to induction of labour with PGE 2 gel or oxytocin only if not in spontaneous labour 24 hours after prelabour rupture of membranes (conservative group). Main outcome measures Number of women in active labour within 24 hours of the prelabour rupture of membranes, preference of women for any one particular method of management in any subsequent pregnancy with prelabour rupture of membranes. Results 93.3% of the active group and 54.8% of the conservative group were in spontaneous labour within 24 hours of the prelabour rupture of membranes (RR 1.7, 95% CI 1.2 to 2.4). Of those achieving a vaginal delivery, 72% of the active group did so within 24 hours of the prelabour rupture of membranes as compared with 26.9% of the conservative group (RR 2.7, 95% CI 1.4 to 5.3, P ¼ 0.002). There were no significant differences in the neonatal or maternal outcomes. In the active group, 78% felt they would have the same method of induction as compared with 40% in the conservative group (RR 1.9, 95% CI 1.1 to 3.3, P ¼ 0.03). Conclusions Active management with oral misoprostol resulted in more women going into labour and delivering within 24 hours of the prelabour rupture of membranes with no increase in maternal or neonatal complications. Women tended to view active management of prelabour rupture of membranes more positively. Oral misoprostol might be an option to consider in those wishing active management.