Purpose: The purpose was to investigate nurse staffing levels and patient outcomes(nosocomial infection, patient fall, pressure ulcer). Method: The subjects of this study were 305 nurses from 20 general hospitals who worked at 39 medical and surgical wards. Self-reporting questionnaire which was developed by the writer through preceding study was used. In data analysis, SPSS WIN 10.0. program was utilized for descriptive statistics, ANOVA. Result: The mean of patient-to-nurse ration was 5.2:1. 65% among 20 hospitals was over 300 beds, 90 was located in urban area and 55 was private hospitals. Patient-to-nurse ration of hospitals in under 300 beds or rural area or private ownership was lower than hospitals in 300 beds or urban area or public ownership. 89.9 among 39 wards was medical or surgical wards. The mean of length of stay, 8-14 days got a majority and showed higher patient-to-nurse ration. Of the general characteristics, rural was significantly hight to patient fall(F=3.205, p<.05), medical unit was significantly high to patient fall, pressure ulcer(patient fall: F=8.890, p<.001, pressure ulcer: F=3.399, p<.05) and over 15 days was significantly higher than under 14 days of the mean of length of stay. And there was significant relationship between over 6.0:1 and over 4.0:1 to less than 5.0:1(F=4.817,p<.01). Conclusion: This study has shown a relationship between patient-to-nurse ration and patient fall using not objective research tool but self-reporting questionnaire. Therefore further research is needed to study using objective research tool. Based on this study, the effect of nurse staffing levels on patient outcome also has to be studied.