Objectives: We compared two doses and intervals of buccal misoprostol for cervical preparation before surgical abortion at 13 to 16 weeks’ gestation. Methods: This blinded randomized trial compared 400 mcg misoprostol administered 3 hours and 600 mcg administered 1.5 hours before surgical abortion. We analyzed results for the primary outcome (procedure time) using a non-inferiority limit of 3 or more minutes. We tested two separate non-inferiority hypotheses each powered at 95% (2.5% confidence interval) for two gestational age groups: 13.0-14.3 and 14.4-15.6 weeks. Assuming 10% withdrawals, we required 118 participants. Secondary outcomes included mechanical dilation, complications, provider satisfaction, and patient side effects and acceptability. Results: The groups did not differ by background characteristics. The shorter misoprostol interval was non-inferior to the longer interval with a mean difference in procedure time of 7.59 seconds (Cl=3.25-4.09 minutes, P=.77). More patients required mechanical dilation in the shorter interval group (97% versus 85%, P=.05). Physicians rated cervical preparation adequate in most cases (97% versus 90%, P=.27). No complications occurred in either group. Side effect severity and satisfaction with the abortion experience did not differ between groups; however, significantly more women in the longer interval group found cervical preparation time unacceptable (15% versus 2%, P=.02). Conclusion: Misoprostol administered in a 600mcg dose over 1.5 hours did not increase operative time by more than the pre