The present study was carried on 150 patients with threatened pretermlabour and intact membranes who were divided into 5 groups. Group 1received ritodrine, group 2 received magnesium sulphate, group 3received nifedipene, group 4 received indomethacin and group 5 receivednitroglycerin. Each group was divided into 2 subgroups; subgroup "A"received prophylactic antibiotics while group "B" did not. Comparisonbetween the drugs revealed non significant difference in their tocolyticpower, but ritodrine and nitroglycerin had many side effects. There wasno significant difference between subgroup "A" and subgroup "B" inprolongation of pregnancy or neonatal outcome.