BACKGROUND The aim of this study was to identify the nosocomial infection (NI) risk factors in neonatal Intensive Care Units (NICU). MATERIAL AND METHODS Databases (PubMed, Embase, Cochrane, VANFUN, CNKI, and VTTMS) were searched using index words to find relevant studies published before November 2018. Meta-analyses of relative risk (RR) were performed for the identification of risk factors. RESULTS Data from 22 cohort studies (2270 infants with and 21 605 infants without NI) were included in the meta-analysis. Infant weight of <2500 g (RR: 3.44, 95% CI: 2.31-5.11), gestational age of <37 weeks (RR: 3.85, 95% CI: 1.87-7.92), mechanical ventilation use (RR: 3.16, 95% CI: 2.21-4.50), venipuncture (RR: 3.01, 95% CI: 1.20-7.57), the incidence of asphyxia (RR: 1.68, 95% CI: 1.04-2.71), and feeding intolerance (RR: 2.12, 95% CI: 1.60-2.81) were identified as the risk factors for the incidence of NI. There was no significant publication bias. CONCLUSIONS This study shows that <2500 g infant body weight, gestational age of <37 weeks, mechanical ventilation utility, venipuncture, asphyxia incidence, and feeding intolerance are the risk factors for NI nosocomial infection in infants in NICU. Appropriate preventive measures and targeted interventions are needed.