Abstract: OBJECTIVE To explore the risk factors and etiological characteristics of nosocomial infection in patients of emergency observation wards. METHODS A total of 435 patients who were treated in the emergency observation wards from Jan 2016 to Jun 2016 were recruited as the study objects, and the risk factors and etiological characteristics of nosocomial infection in the enrolled patients were observed. RESULTS Of the 435 patients who were treated in the emergency observation wards, 51 had nosocomial infection, 35.29% of whom had respiratory tract infection, 27.45% had gastrointestinal tract infection, 15.69% had urinary tract infection, and 13.73% had skin and soft tissue infection. Totally 85 strains of pathogens were isolated from the blood specimens that were collected from the 51 patients complicated with nosocomial infection, 25.88% of which were Pseudomonas aeruginosa, and 23.53% were Streptococcus pneumoniae. The P.aeruginosa strains were highly susceptible to imipenem but were highly resistant to amoxicillin; the S.pneumoniae strains were highly susceptible to linezolid, teicoplanin and vancomycin but were highly resistant to cefaclor, cefalotin and cefoxitin. The no less than 65 years of age, assisted invasive breathing, urinary catheter indwelling, deep venous catheter indwelling, observation time more than 3 days and use of hormone drugs were the independent risk factors for the nosocomial infection in the patients of emergency observation wards (P<0.05). CONCLUSION There are a variety of factors for the nosocomial infection in the patients of emergency observation wards. It is necessary to evaluate the risk of infection in a timely manner and take targeted interventions.