Purpose: This study was conducted to investigate and compare the characteristics and relations of nursing practice environment, professionalism and job satisfaction among nurses in general hospitals according to hospital size. Methods: The participants included 314 staff and charge nurses who were working in the general medical/surgical nursing units in one large hospital, three medium sized hospitals, and four small hospitals. Data collected through using self-report questionnaire were analyzed using the SPSS and SAS statistical programs. Results: Nursing practice environment and job satisfaction had significant differences according to hospital size. Both of these scales were highest for medium hospitals and lowest for small hospitals. For all hospital sizes there were positive correlations between each of the variables. Multiple regression analysis showed that both nursing practice environment and job satisfaction were affected by hospital size, but professionalism was not. Conclusion: The results of this study indicate that nursing practice environment and job satisfaction vary with the size of the hospital. Therefore, further study is necessary to identify the work environment variables of nurses for performance management and to implement appropriate policies.