Objectives: Objectives: Despite efforts to improve acute postoperative pain management, a substantial number of patients still experience moderate to severe pain during the immediate postoperative days. The purpose of the present study was to identify predictors of moderate to severe acute postoperative pain. Methods: Methods: A total of 1490 patients undergoing heterogeneous Surgical procedures recorded their pain 3 times a day oil a 100-mm visual analog scale front the day before the operation until 5 days postoperation. For each postoperative day, pain intensity was classified as moderate when the mean pain score was 41 to 74mm and as "severe when the mean pain score was 75 to 100 turn. Using logistic regression analyses. we examined the predictive value of a comprehensive set of preoperative and perioperative variables for moderate to severe pain. Results: Results: The most important predictors seemed to be; preoperative pain, expected pain, Surgical fear, and pain catastrophizing. Discussion: Discussion: Several predictive factors of postoperative pain were identified in this study. These factors could be taken into account in postoperative pain management.