This study was designed to measure the degree of work stress perceived by clinical nurses working in psychiatric ward, and to identify the factors influencing the difference of work stress. The survey method was used and the subjects of this study consisted of 135 psyciatric nurses from 7 university hospitals and 4 provincial general hospitals, The data were collected from August 1 to 20, 198 8. The instrument used for this study was PNOSS (Psychiatric Nurse Occupational Stress Scale) which was developed by Bai(1989). The confidence verific ation of this instrument was computed and the Cron -bach a was 0.94050. Data were analysed by t-test and ANOVA on 5 % significant level with SPSS program. The results of study were summerized as follow : 1) The degree of perceived stress among psychiatric nurses was considerably high (4.32 out of 6.00). 2) Among the stressors, inadequate staffing(5.04), hospital administrational problems (4.7) and the conflict of nurse-patient relationship were identified as the stress factors with high rank of degree of stress. 3) There was significant relationship between the degree of stress and the demographic variables of nurses such as the marital status, educational level, and the motivation of working in psychiatric ward. 4) There was significant relationship between the job-related variables such as the working duration, the motivation of working and nurse's attitude toward the psychiatric patients. 5) The relationship between several stress factors and some of the demographic and the job-related variables were significantly identified.