In opposition to Mexico City's legalization of first-trimester abortion, 17 Mexican states (53 percent) have introduced initiatives or reforms to ban abortion entirely, and other states have similar legislation pending. We conducted an opinion survey in eight states—four where constitutional amendments have already been approved and four with pending amendments. Using logistic regression analyses, we found that higher education, political party affiliation, and awareness of reforms/initiatives were significantly associated with support for the Mexico City law. Legal abortion was supported by a large proportion of respondents in cases of rape (45–70 percent), risk to a woman's life (55–71 percent), and risk to a woman's health (48–68 percent). A larger percentage of respondents favored the Mexico City law, which limits elective legal abortion to the first 12 weeks of gestation (32–54 percent), than elective abortion without regard to gestational limit (14–31 percent).