Abstract:ObjectiveTo explore the risk factors for nosocomial methicillinresistant Staphylococcus aureus (MRSA) infection, so as to provide a scientific basis for taking effective measures to reduce nosocomial MRSA infection rates.Methods1:1 casecontrol study was performed, 108 pairs of research subjects were included in the research. Questionnaires were designed to study the history of case and control data. Multivariate nonconditional Logistic regression and chisquare test were used to analyze the data.ResultsAnalysis showed that the following factors were associated with nosocomial MRSA infection: old age (≥ 65 years old, P= 0.013), length of stay in hospital (P<0.001), the types of underlying disease (P<0.001), the number of invasive procedures (P<0.001), broadspectrum antimicrobial use(P<0.001), types of antimicrobial agents (P= 0.004) and duration use of antimicrobial agents (P<0.001). Multivariate analysis showed that the main risk factors related to nosocomial MRSA infection included length of stay in hospital (P<0.001), the number of invasive procedures (P= 0.001), types of used antimicrobial (P= 0.001) and duration use of antimicrobials (P<0.001).Conclusion Risk factors for nosocomial MRSA infections are long length of stay in hospital , frequent invasive operations , and longterm as well as multiple use of broadspectrum antimicrobial agents.