Objectives：The cost of psychiatric service is increasing every year in Korea. The length of inpatient stay (LOS) is an important factor determining in-patient service cost. This study was aimed to find the factors that influence LOS in a psychiatric open ward of a general hospital. Methods：The study includes 134 inpatients who were consecutively admitted to a psychiatric open ward in a general hospital from January 1st to June 30th in 2001. Demographic data, clinical characteristics on admission and discharge, global functioning, social support levels and life stressors were collected. Results：The mean LOS for the 134 patients was 15.5 days (S.D 9.2). The occupation of housekeeper and those secred high in phobic anxiety subscale on SCL-90-R were statistically significant predictor for longer LOS in the univariate analysis. No significant differences in LOS were found by diagnostic groups and social support. In multiple regression analysis, the scores of phobic anxiety subscale, occupation and presence of physical illness were statistically significant predictor for LOS. Conclusion：This study failed to find the significant variables to account for substantial proportion of variance for LOS.