Aim: To evaluate and compare effectiveness, side effects and patient acceptability between oral and sublingual 600 µg misoprostol for the treatment of incomplete abortion.Methods: A randomized controlled trial was conducted. Pregnant women of less than 14 weeks gestation, diagnosed with incomplete abortion, were randomly assigned to receive 600 µg misoprostol orally or sublingually. The patients were evaluated at 48 h after drug administration for complete abortion.Results: A total of 64 women were recruited to the study (32 in the oral group and 32 in the sublingual group). The complete abortion rate was not statistically different between oral and sublingual groups (87.5% versus 84.4%, P > 0.05). There was no statistical difference in side effects and satisfaction rate. Fever/chills were the most common side effects.Conclusion: Both sublingual and oral 600 µg misoprostol are useful for the management of incomplete abortion. Side effects and satisfaction rates are not different. Thus, these methods may be used as alternative treatments of incomplete abortion.