Objectives. To analyze the practice of surgical intensive care unit (SICU) admission of postoperative urologic patients and to define objective criteria to predict active treatment requirements and length of stay in the SICU.Methods. The records of 90 consecutive patients admitted to the SICU postoperatively in the 12-month period from January 1996 to December 1996 were retrospectively reviewed. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was calculated from patient parameters acquired within the first 12 hours. The correlation of outcome variables to the length of stay and the requirements for active treatment in the SICU were analyzed and used to develop a risk stratification model. This algorithm was subsequently validated on a population of 46 patients who underwent radical cystectomy the following year.Results. Only the preoperative American Society of Anesthesia class, the event of an intraoperative complication, and the APACHE II score were statistically significant (P <0.05) predictors of length of stay and active treatment. The patients were subsequently categorized into high and low-risk groups, which were found to have mean SICU stays of 39.9 ± 3.92 hours and 20.2 ± 0.45 hours, respectively (P = 0.001), and an active SICU-specific treatment rate of 58.0% and 14.3%, respectively (P = 0.001). These results were confirmed in the validation population.Conclusions. Postoperative risk stratification may be helpful in predicting SICU requirements in the immediate postoperative period and in identifying patients at lower or higher risk of an adverse outcome. Copyright (C) 2000 Elsevier Science Inc.