Quality improvement initiatives in neonatology have yielded positive results; however, few programs have demonstrated sustainability. We evaluated an ongoing, national quality improvement initiative (Evidence-based Practice for Improving Quality Phase 3 (EPIQ-3)) on outcomes of preterm neonates with a gestational age (GA) of 220–286 weeks (i.e., from 22 weeks and 0 days of gestation to 28 weeks and 6 days of gestation). Data from 7459 neonates admitted to 25 Canadian centers between 2013 and 2017 were studied. Trends in mortality and major morbidities were evaluated. The number of neonates with a GA of 220–236 weeks increased from 90 in 2013 to 139 in 2017 without a significant change in any other GA categories. In the entire cohort, the odds of composite outcome of mortality or any major morbidity (adjusted odds ratio (AOR) 0.72, 95% confidence interval (CI) 0.61–0.84) and of necrotizing enterocolitis (AOR 0.66, 95% CI 0.49–0.89) were lower in 2017 than in 2013. When calculated per year, the odds of composite outcome (AOR 0.93, 95% CI 0.89–0.97) and odds of necrotizing enterocolitis (AOR 0.89, 95% CI 0.82–0.96) decreased significantly. Among the subgroup of neonates with a GA of 260–286 weeks, the odds of composite outcome (AOR 0.63, 95% CI 0.51–0.79), necrotizing enterocolitis (AOR 0.44, 95% CI 0.26–0.73), and nosocomial infection (AOR 0.64, 95% CI 0.49–0.84) were reduced. The collaborative, multidisciplinary, nationwide EPIQ-3 program improved outcomes of preterm neonates, and the improvement was sustainable over 5 years.