Cost sharing may impede postpartum contraceptive use. We evaluated the association between out-of-pocket costs and long-acting reversible contraceptive (LARC) insertion among commercially insured postpartum women.Using the Clinformatics Data Mart, we examined out-of-pocket costs for LARC insertions at 0 to 3 and 4-60 days postpartum among women in employer-sponsored health plans from 2013 to 2016. Patient costs were estimated by summing copayment, coinsurance, and deductible payments for LARC services (device + placement). Multivariable logistic regression evaluated the association between plan cost sharing for LARC services (at least one beneficiary with >$200 cost share) and LARC insertion by 60 days postpartum (yes/no).We identified 396,073 deliveries among women in 51,797 employer-based plans. Overall, LARC placement by 60 days postpartum was observed after 5.2% (n = 20,604) of deliveries. Inpatient LARC insertion (n = 233; 0.06% of deliveries) was less common than outpatient LARC insertion (n = 20,375; 5.14% of deliveries). Cost sharing was observed in 23.4% of LARC insertions (inpatient IUD: median, $50.00; range, $0.93-$5,055.91; inpatient implant: median, $11.91; range, $2.49-650.14; outpatient IUD: median, $25.00; range, $0.01-3,354.80; outpatient implant: median, $27.20; range, $0.18-2,444.01). Among 5,895 plans with at least one LARC insertion and after adjusting for patient age, poverty status, race/ethnicity, region, and plan type, women in plans with cost sharing of more than $200 demonstrated lower odds of LARC use by 60 days postpartum (odds ratio, 0.74; 95% confidence interval, 0.71-0.77).Cost sharing for postpartum LARC is associated with use, suggesting that out-of-pocket costs may impede LARC access for some commercially insured postpartum women. Reducing out-of-pocket costs for the most effective forms of contraception may increase use.