This paper is a prospective study of the outcome of labour in 109 patients with favourable and unfavourable cervices in whom labour was induced by intravaginal prostaglandin, with supplementary syntocinon infusion where necessary. There were 61 primigravidae and 48 multigravidae. The rate of operative intervention was virtually no higher than in those labours of spontaneous onset. The length of labour varied inversely with the Bishop score of the cervix before induction, with a coefficient of correlation of -0·995 for primigravidae and of -0·929 for multigravidae. Bishop score was shown to be a poor indicator of the number of doses of prostaglandin needed for successful induction.