Purpose: The purpose of this study was to examine the frequency and the course of delirium, and identify risk factors for the development of delirium in surgical intensive care unit (SICU). Methods: Subjects older than 19 years admitted to the SICU were recruited. After informed written consent, enrolled subjects had baseline cognitive and functional assessments. Subjects were assessed daily for delirium using the Confusion Assessment Method-ICU (CAM-ICU). Results: During the study period, 110 patients were enrolled. The overall incidence of delirium was 20% (22/110). The average time to onset of delirium was 3.04(${pm}1.25$) days. Several variables were associated with an increased risk of delirium including older age (p<.05), higher admission APACHE II score (p<.001), use of opioid and analgesics (p<.01), using physical restraints (p<.001), and intraoperative hypotension (p<.05). In a multivariate logistic regression model, using physical restraints (p<.001), intraoperative hypotension (p<.05), and older age (p<.05) remained significant predictors of the delirium development. Conclusion: Using physical restraints, intraoperative hypotension and older age was strongly associated with development of delirium in the SICU. Prevention measures need to focus on identifying patients at higher risk for delirium development.