Objectives In the 1980s, policy makers in Mexico led a national family planning initiative focused, in part, on postpartum IUD use. The transformative impact of this initiative is not well known, and is relevant to current efforts in the United States (US) to increase women’s use of long-acting reversible contraception (LARC). Methods Using six nationally representative surveys, we illustrate the dramatic expansion of postpartum LARC in Mexico and compare recent estimates of LARC use immediately following delivery through 18 months postpartum to estimates from the US. We also examine unmet demand for postpartum LARC among 321 Mexican-origin women interviewed in a prospective study on postpartum contraception in Texas in 2012, and describe differences in the Mexican and US service environments using a case study with one of these women. Results Between 1987 and 2014, postpartum LARC use in Mexico doubled, increasing from 9 to 19 % immediately postpartum and from 13 to 26 % by 18 months following delivery. In the US, <0.1 % of women used an IUD or implant immediately following delivery and only 9 % used one of these methods at 18 months. Among postpartum Mexican-origin women in Texas, 52 % of women wanted to use a LARC method at 6 months following delivery, but only 8 % used one. The case study revealed provider and financial barriers to postpartum LARC use. Conclusions Some of the strategies used by Mexico’s health authorities in the 1980s, including widespread training of physicians in immediate postpartum insertion of IUDs, could facilitate women’s voluntary initiation of postpartum LARC in the US.