Purpose: This study was conducted to evaluate quality of sleep and to assess the factors that influence quality of sleep in surgical ICU. Methods: The subject of the study were consisted 109 adult patients who admitted to surgical ICU. The data were collected from May 20 to December 10, 2007 by structured questionnaires. The data were analyzed with descriptive analysis, paired t-test, Pearson correlation coefficient and stepwise multiple regression. Results: The score of quality of sleep was 4.57 point. The main sleep disturbance factors related to quality of sleep in surgical ICU inpatient were sleep time, machinery alarm and noise(adjusted $R^2$=33.2). Conclusion: Based on the finding of this study, it is needed to develop a nursing intervention program that including to promote quality of sleep and to decrease machinery alarm and noise in surgical ICU.