The prevalence of facility-based childbirth in low-resource settings has increased dramatically during the past two decades, yet gaps in the quality of care persist and mortality remains high. The World Health Organization (WHO) Safe Childbirth Checklist, a quality-improvement tool, promotes systematic adherence to practices that have been associated with improved childbirth outcomes.We conducted a matched-pair, cluster-randomized, controlled trial in 60 pairs of facilities across 24 districts of Uttar Pradesh, India, testing the effect of the BetterBirth program, an 8-month coaching-based implementation of the Safe Childbirth Checklist, on a composite outcome of perinatal death, maternal death, or maternal severe complications within 7 days after delivery. Outcomes - assessed 8 to 42 days after delivery - were compared between the intervention group and the control group with adjustment for clustering and matching. We also compared birth attendants' adherence to 18 essential birth practices in 15 matched pairs of facilities at 2 and 12 months after the initiation of the intervention.Of 161,107 eligible women, we enrolled 157,689 (97.9%) and determined 7-day outcomes for 157,145 (99.7%) mother-newborn dyads. Among 4888 observed births, birth attendants' mean practice adherence was significantly higher in the intervention group than in the control group (72.8% vs. 41.7% at 2 months; 61.7% vs. 43.9% at 12 months; P<0.001 for both comparisons). However, there was no significant difference between the trial groups either in the composite primary outcome (15.1% in the intervention group and 15.3% in the control group; relative risk, 0.99; 95% confidence interval, 0.83 to 1.18; P=0.90) or in secondary maternal or perinatal adverse outcomes.Birth attendants' adherence to essential birth practices was higher in facilities that used the coaching-based WHO Safe Childbirth Checklist program than in those that did not, but maternal and perinatal mortality and maternal morbidity did not differ significantly between the two groups. (Funded by the Bill and Melinda Gates Foundation; Clinical Trials number, NCT02148952 .).