Background Prolonged labour is a major problem in obstetrics and it is associated with significant maternal and neonatal mortality and morbidity. The duration of labour is determined by the rate of cervical dilatation among other factors. Enhancing cervical dilatation in labour helps in shortening the duration of labour in the absence of other mitigating factors thereby preventing prolonged labour with its attendant complications. This fact has led to studies on the role of hyoscine butyl bromide in accelerating cervical dilatation as a way of preventing prolonged labour. Aim of the study The aim of this study was to evaluate the efficacy of hyoscine butyl bromide in accelerating cervical dilatation in labour Methodology This was a double blind randomised controlled study done at National Hospital Abuja, in which 130 parturients (nulliparous and parous) in spontaneous labour were randomised into one of two parallel treatment groups in the allocation ratio of 1:1. The study group received a single dose of 20mg of hyoscine butyl bromide intramuscularly on diagnosis of active phase of labour while the control group received 1ml of distilled water. The primary outcome measure was the duration of the first stage of labour. The secondary outcomes measures were the duration of the second and third stages of labour, blood loss at delivery, maternal drug side effects and immediate neonatal outcome.