As the twenty-first century approaches, nurses face rapid changes in health policy, complicated nurse-patient relationships, high-technological medical treatment and concerns dealing with aging patients. Thus, work related stress among nurses is increasingly predominate. The purposes of this study is to understand the work stress level of nurses as well as related personal and work factors within a medical center. A cross-sectional study design was applied for this study and the nurse stress checklist was used as the research instrument. 533 nurses were selected by systemic random sampling and 511 valid checklists were collected. Pearson correlation coefficient, t-test and ANOVA were used to analyze the data. The results show that the mean score of the nurse stress checklist was similar to the mean score of nurses working in the United States. As for the related factors, the study indicated that younger nurses those with less work experience (under one year, especially), and those not married, scored highest for work related stress. The difference between work stress in nurses working in critical care units and medical-surgical units was not significantly different. Nurses working in primary nursing care units had the lowest work stress of all other samples. Based on these results, the following suggestions are recommended; Plan guidance and stress management strategies for first year nurses; Apply primary nursing care model in order to reduce stress.