Context Necrotizing enterocolitis (NEC) is the most frequent gastrointestinal emergency in neonates. The microbiome of the preterm gut may regulate the integrity of the intestinal mucosa. Probiotics may positively contribute to mucosal integrity, potentially reducing the risk of NEC in neonates. Objective To perform an updated systematic review and meta-analysis on the efficacy and safety of probiotics for the prevention of NEC in premature infants. Data Sources Structured searches were performed in: Medline, Embase, and the Cochrane Central Register of Controlled Trials (all via Ovid, from 2013 to January 2015). Clinical trial registries and electronically available conference materials were also searched. An updated search was conducted June 3, 2016. Study Selection Randomized trials including infants less than 37 weeks gestational age or less than 2500 g on probiotic vs. standard therapy. Data Extraction Data extraction of the newly-identified trials with a double check of the previouslyidentified trials was performed using a standardized data collection tool. Results Thirteen additional trials (n = 5033) were found. The incidence of severe NEC (RR 0.53 [95% CI 0.42 to 0.66]) and all-cause mortality (RR 0.79[95% CI 0.68 to 0.93]) were reduced. No difference was shown in culture-proven sepsis RR 0.88 [95% CI 0.77 to 1.00]. Limitations Heterogeneity of organisms and dosing regimens studied prevent a species-specific treatment recommendation from being made. Conclusions Preterm infants benefit from probiotics to prevent severe NEC and death.