OBJECTIVE To measure the prevalence of believing that abortion should be illegal in all or most cases among women obtaining an abortion in the United States and to identify correlates of holding this belief. METHODS Study population was drawn from the nationally-representative 2008 Abortion Patient Survey. The primary outcome was having an anti-legal abortion attitude, defined as agreeing that abortion should be illegal in all or most cases. We assessed potential correlates in bivariable and multivariable analyses using weights to account for the complex sampling. RESULTS A total of 4769 abortion patients completed the survey module containing the question on abortion legality, of which 4492 (94.2%) had non-missing data for the outcome. Overall, 4.1% of patients (N=183) reported an anti-legal abortion attitude. Correlates of having anti-legal attitude included being married, at <200% federal poverty level, fundamentalist, contraception non-use, no abortion history, perceiving the pregnancy with ambivalence or as unintended, and using misoprostol or another product on their own to bring back their period or end the pregnancy. CONCLUSIONS Abortion patients who do not believe abortion should be legal appear to differ substantially from women who are more supportive of legality. Findings raise important questions about this subset of patients, including whether possible discordance between patient beliefs and behavior could influence their use of medical abortion or other products. CONCLUSIONS Some abortion patients do not agree with abortion legality, and this subset could experience a degree of cognitive dissonance, which could influence the method by which they seek to abort.