Beginning in 1958, Dr. Edris Rice-Wray established the Asociación Pro-Salud Maternal (Association for Maternal Health) clinics in Mexico where low-income women could explore family planning options. Using transnational collaborations to fund and supply contraception across the US-Mexico border, the asociación created space for women to claim their reproductive rights. The subsequent increased pressure from urban women, their priests, and their doctors for access to birth control forced the state to accommodate their needs by changing national family planning laws in 1974. This article examines the transnational work of Rice-Wray to reveal the political, religious, social, and economic challenges to birth control experienced by women in mid-twentieth-century Mexico.