Objective To systematically evaluate the risk factors associated with the occurrence of nosocomial infections(NI)in patients undergoing extracorporeal membrane oxygenation(ECMO)support.Methods A computerized systematic search was performed aross the Chinese databases including CNKI,Wanfang Database,China Biomedical Literature Database(CBMdisc),and Weipu,as well as the English databases such as PubMed,EMBase,Web of Science,and the Cochrane Library for case-control or cohort studies on the risk factors of hospital-acquired infections in patients undergoing ECMO support from the time of database construction to February 2023.The relevant literatures were screened by two researchers independently.Meta-analysis was performed using RevMan 5.4 software.Results A total of 20 papers,including 2 746 patients and 16 risk factors,were included.Meta-analysis results showed that older age[>50 years:odds ratio(OR)= 2.87,95％ confidence interval(95％ CI)was 1.24-6.63,P = 0.01;>65 years:OR = 1.66,95％ CI was 1.22-2.26,P = 0.001],combined hypertension(OR = 1.48,95％ CI was 1.01-2.15,P = 0.04),combined diabetes mellitus(OR = 1.40,95％ CI was 1.02-1.94,P = 0.04),sequential organ failure assessment(SOFA)was higher(OR = 1.06,95％ CI was 1.02-1.10,P = 0.000 7),the installation of ECMO in the intensive care unit(ICU,OR=1.48,95％ Ciwas 1.11-1.99,P=0.008),ECMO course(OR=1.27,95％ Ciwas 1.05-1.54,P = 0.01),ventilator-assistance for >48 hours(OR = 4.91,95％ CI was 2.40-10.05,P<0.000 1),and tracheotomy(OR = 9.56,95％ CI was 3.60-25.35,P<0.000 01)were identified as ECMO risk factors for hospital-acquired infections in patients.Conclusion Older age,combined hypertension,diabetes mellitus,higher SOFA,ECMO installation site in ICU,ECMO course,ventilator assistance>48 hours,tracheotomy are the risk factors for the occurrence of hospital-acquired infections in patients with ECMO,healthcare professionals should promptly identify the risk factors related to hospital-acquired infections,and take active and effective measures against controllable risk factors,including early intervention to prevent the occurrence of NI in ECMO patients.