Necrotizing enterocolitis (NEC) carries high rates of mortality and morbidity in perterm infants. Our NEC rates over 6 years, were in higher quartiles of the Vermont-Oxford Network and prompted an improvement project. To reduce NEC rates by 30% from 4.5% to 3% by 3/2016 in <33 weeks infants admitted in Sunnybrook NICU. Multi-professional team used fishbone analyses, process maps, literature review and compliance with hospital Infection Prevention unit. A product was selected (BioGaia, Lactobacillus reuteri; Ferring, Sweden). A policy written and approved. As a forcing mechanism, order for probiotics added to admission orders set. We gave education to staff, parents. We started after a cluster of cases (‘burning platform’). PDSA#1 on the first baby was in 2/2015. After first month, issues were addressed, then spot audits assured continuing compliance. Measures: Outcome measures: NEC in infants<33 wk GA, (>=stage 2), Sepsis, Mortality. Secondary outcomes: Sepsis evaluations, Feeding intolerance, Days NPO, Growth rate/week, Antibiotics days, TPN days, Formula days. Process measures: Compliance rate, Probiotics days. Balancing measures: Sepsis, Feeding intolerance One year before (planning periods, 330 infants), and two years into implementation (745 infants). NEC rates declined from 4.3% to a current rate of 1.3%. P-chart of NEC show a sustained reduction, P-chart of compliance shows a sustained compliance. Other outcomes detailed in Table 1. No significant baseline differences. Our QI project used QI tools – teamwork, RCA, aim statement, drivers, standardisation, forcing mechanisms, education, PDSA, and SPC. All supported a feasible, effective, safe, and sustained improvement. Findings are consistent with previous RCTs. p Chart:% infants<33 wks given biogaia p Chart: NEC rates, infants<33 wks GA Baseline charactreristics and outcomes