Objective: To determine the timing of insertion of the levonorgestrel intrauterine system (LNG-IUS), post-placental versus interval, that results in the highest rate of LNG-IUS in place by exam at 6-months. Materials and Methods: A randomized control trial of women >36 weeks gestation who underwent vaginal delivery of a singleton and desired LNG-IUS for contraception. Women were randomized to insertion within 10-minutes of placenta delivery (IMMEDIATE) or insertion at 4-8 weeks post-partum (INTERVAL). The primary outcome was LNG-IUS in place by physical exam at 6-months. Secondary outcomes were reported LNG-IUS use at 6-months, number of LNG-IUS placed, uterine perforations, and intrauterine infections. Results: Of 53 women enrolled in the study, 29 were randomized: 15 to IMMEDIATE and 14 to interval insertion. All 15 women randomized to IMMEDIATE received the LNG-IUS; 10/14 (71%) women randomized to INTERVAL received the LNG-IUS (p=0.03). Three expulsions occurred in IMMEDIATE (20.0%) and all three had the LNG-IUS replaced. At 6 months, 10/15 women in IMMEDIATE had an LNG-IUS confirmed in place, versus 3/14 in INTERVAL (p=0.01), although this difference may be due to differences in follow up. Conclusions: LNG-IUS insertion immediately after delivery of the placenta may be appropriate in women at high-risk for being lost to follow up.