Slow release prostaglandin pessary (propess) is compared with instant release prostaglandin gel (prostin) for the induction of labour in nulliparous women with a modified Bishop's score of less than 6. In this randomised study 50 women received prostin gel and 45 received propess. More than one dose of prostaglandin was required to achieve amniotomy more often in the propess group (53%) compared with the prostin group (34%) ( P =0·03). Propess was unable to demonstrate any advantage over Prostin gel group. Propess was not cost-effective in this study.