In view of the lack of information regarding abortion attitudes in Mexico, an abortion opinion survey was conducted in Mexico City among 387 women and 338 men. Respondents were asked if they agreed with a woman's abortion decision under seven different circumstances. Affirmative responses were analyzed by respondents' sociodemographic and reproductive health characteristics and a scale was created to measure respondents' overall attitudes toward abortion. Greatest support was expressed for a woman's right to an abortion, and to abortion in cases of fetal defect, threat to the mother's life, and rape. On the attitudinal scale, however, respondents generally disapproved abortion. Male respondents were more likely than female respondents to support a woman's abortion decision. Males in union, females not in union, respondents over thirty years of age, those with more than primary school education, those with fewer pregnancies, those with no history of child mortality, and those with a history of or experience with abortion, were also more likely to support an abortion decision.