Background: Prematurity and its prevention continue to be a major challenge for both the obstetrician and neonatologist. Preterm labour is the most common obstetrical complication associated with perinatal deaths. Despite all advances in neonatology, the delivery of a preterm neonate is a clinical crisis that threatens the life and health of an infant. The obstetrician thus faces the challenge of affecting the delivery in such a way as to optimize the status of fetus-infant at birth. It is far more preferable to prevent the intiation of preterm labour than once the cascade of events has already been established. Objective: To assess the efficacy of magnesium sulphate as a tocolytic agent in preterm labour. Material and Methods: 50 pregnant patients with gestational age 28- 37 weeks with cervical dilatation not more than 3cm and cervical effacement not more than 50 % with intact membranes with regular uterine contractions with a frequency of 2 or more per 10 minutes lasting for at least 30 seconds were put on magnesium sulphate. Results: Magnesium sulphate was successful in attaining tocolysis in majority of patients and had no adverse effects on immediate neonatal out come. Conclusion: Magnesium sulphate is effective, safe and well tolerated tocolytic agent with no adverse effects on the fetus-infant.