Objective This study aims to compare the efficacy and safety of different doses of vaginal misoprostol prior to IUCD insertion among women with nulliparous cervix “those who 29never delivered-vaginally”. Study design: The current study was a randomized, double-blind, placebo-controlled trial conducted in the Family Planning Clinic of Ain Shams University’s Maternity Hospital Egypt. It involved women who delivered only by elective CD (cesarean delivery). One hundred and eighty women were randomized into three groups, Group 1 received misoprostol 200 mcg. Group 2 received misoprostol 100 mcg. Group 3 received placebo. The primary outcome was pain scores which were measured using a visual analogue scale (VAS), the secondary outcome was the ease of insertion score (ES). Results VAS and ES were significantly lower in group 1 compared to group 2 and group 3 (P < 0.001).There was insignificant difference among the three groups as regards successful IUD insertion (P = 0.477). Duration of insertion was significantly lower in group 1 than group 2 (P < 0.001). Satisfaction was significantly higher in group 1 compared to group 2 and group 3 (P < 0.001) Conclusion The effect of misoprostol seems to be dose-dependent. Dose of 200mcg seems to be ideal with best efficacy and with no significant increase in the adverse effects Implications: The dose of 200mcg vaginal misoprostol prior to IUD insertion in women, who had never delivered vaginally before, seems to be the most effective dose. Trail to lower the dose to100mcg significantly compromises the efficacy without remarkable benefit on the side effect profile.