 Misoprostol, a prostaglandin analogue, is principally used to prevent peptic ulcer disease induced by nonsteroidal anti-inflammatory agents .It has been shown to induce second trimester abortion .However , the optimal regimen has not been determined .Studies have used doses ranging 200- 800 microgram misoprostol at interval ranging from 3-12 hours.1,2,3,4,5 In our previous study we have compared intravaginal misoprostol with extra amniotic ethacridine lactate for second trimester MTP.6 In this study we have observed that misoprostol is highly effective success rate 95 for second trimester MTP with minimal side effects . intravaginal misoprostol results in significantly shorter induction abortion interval in comparison to extra amniotic ethacridine lactate .Induction abortion interval in this study for misoprostol was 15.5 hours and the dosage of misoprostol was 400 microgram vaginally every 12 hours with a maximum of 4 doses .Success rate and induction abortion interval are the major factors of clinical importance for second trimester MTP . Our aim is to establish a dosage schedule of misoprostol which will result in high success rate in mid trimester MTP with further shortening of induction abortion interval Our study hypothesis is that using 400 microgram of vaginal misoprostol at six hour interval will result in significant shortening of induction abortion interval in comparison to 400 microgram vaginal misoprostol at 12 hour interval. 