Background: Postoperative ileus is a well-known consequence and complication of gastrointestinal, pelvic, and some non-abdominal surgeries, resulting in significant morbidity and patient discomfort and dissatisfaction. It is a virtually universal complication after abdominal surgery that prolongs duration of hospitalization. Postoperative ileus has a great economic burden and, interestingly, it was as expensive as managing severe postoperative complications (such as deep venous thrombosis, pulmonary embolism, and surgical site infection) that might not lead to ileus. Objective: The main objective of this study is to assess the magnitude and associated risk factors of postoperative ileus among adult patients underwent abdominal surgery at Tibebe Gihon specialize hospital & Felegehiwot Comprehensive Specialize Hospital, Bahirdar, Ethiopia Method: Institution based multicenter cross-sectional study was conducted on patients who underwent abdominal surgeries at governmental specialized hospital in Bahirdar from September 20 to November 20 2023. A total of 252 selected from the two hospitals by consecutive sampling techniques and included in the final analysis. Before being imported into STATA/MP version 17, the data were originally input into Epidata version 4.6. The analysis fitted in bivariable and multivariable binary logistic models to find the explanatory variables. The 95% confidence interval of the odds ratio was calculated, and factors with a p-value less than 0.05 in the multivariable model were declared significantly associated with the dependent variable. Results: Themagnitude of Postoperative ileus at selected hospitals in Bahir Dar was16.27% (95% CI: 12.19%, 21.38%).Age (AOR= 3.81, 95%CI: 1.41, 10.33), BMI(AOR= 11.54, 95%CI: 1.97, 67.55),intestine surgery (AOR= 3.27, 95% CI: 1.01, 11.77)were significantly associated with Postoperative ileus. On the other hand being female decrease the risk of Postoperative ileus by 61 %(AOR= 0.39, 95%CI: 0.15, 0.97). Conclusion: Magnitude of Postoperative ileus among patients underwent abdominal surgery in Bahir Dar was an average when compare it with results reported from different studies. Old age, male sex, low BMI and intestinal surgeries were significant determinant factors associated with Postoperative ileus.