AIMS:The aim of the present study was to compare the levels of stress, depression, and intention to leave among clinical nurses employed in different medical units in relation to their demographic characteristics under the National Health Insurance (NHI) System in Taiwan. METHODS:Cross-sectional Spearman's correlation, one-way ANOVA with Scheffe post hoc analysis tests, and multiple regression analyses were conducted. Several self-report questionnaires, such as the Center for Epidemiological Studies Depression Scale, the Perceived Stress Scale and Intention to Leave Scale, were administered. A total of 314 research participants were surveyed, all of whom came from regional hospitals in Northern Taiwan. RESULTS:Marital status and working tenure were significant predictors to the levels of stress, depression, and intention to leave among nurses before taking the medical units into consideration. However, with adding medical units as predictors, the effect of marital status and working tenure were insignificant except for the stress model, indicating medical units were showing dominant effect over other variables. In particular, internal medical ward (IMW) nurses experienced a higher prevalence of depression than emergency room (ER) nurses and professional nursing practitioners. External medical ward (EMW) nurses also experienced greater depression than emergency room (ER) nurses. Both IMW and EMW nurses perceived significantly greater stress than ER and dialysis center. Moreover, IMW nurses also perceived greater stress than operating room (OR) nurses and showed stronger intention to leave than their counterparts in the outpatient service departments. CONCLUSIONS:The results indicated that significant differences existed among various medical units with regards to nurses' stress, depression, and intention to leave. Nurses working in internal and external medical wards, especially the inexperienced and married ones, experienced greater depression and stress, thereby developing stronger intention to leave their job.