Background: Abortion is the most common subjects of obstetric which has applied two methods including surgical and medical approaches. Pain is the most common complication of medical abortion and pain relief is one the most important items in these patients.Objectives: Evaluated the effect of three non-steroidal anti-inflammatory drugs in pain reduction of medical abortion in less than 14 weeks gestation with forensics declaration. Methods:This study was a retrospective cohort in 66 pregnant women with less than 14 weeks gestation referred to Yas hospital for medical abortion that were assigned to three groups based on sedative drugs: A) Mefenamic acid capsules 250 mg, B) Diclofenac tablets 100 mg and C) Ibuprofen tablets 400 mg. The standardized visual assessment scale was assessed before and after drug administration that presented in medical records of patients. Results:Comparison of visual assessment scale means before and after using of three non-steroidal antiinflammatory drugs demonstrated that all three drugs lead to pain relief after the abortion that was significant statistically (P value=0.001). There was a significant difference in termination time of pregnancy between three groups, (P value= 0.016). In the case of hemoglobin drop, diclofenac lead to the lowest hemoglobin drop (P value=0.004). The amount of receiving narcotic among three groups revealed the significant difference (P value= 0.000). There were not significant differences in pain relief (P value=0.327) and demographic data between three groups. Conclusion:It was indicated that the three NSAIDs drugs, had a significant effect on the management of pain, diclofenac expended less termination time of pregnancy, narcotic drug usage and also hemoglobin drop than other groups.What does this study add? Non-steroidal anti-inflammatory drugs are effective in pain management of medical abortion and some of them are preferred to others. Diclofenac can reduce abortion time and also hemoglobin drop after abortion and additional dose of other narcotics too.