Background: - Bowel obstruction is a mechanical or functional obstruction of bowel that prevents the normal movements of products of digestions. Even if Treatment outcome of bowel obstruction varies from area to area, time to time, and also increasing age is significant factor of treatment outcomes of bowel obstruction. Outcome of bowel obstruction and associated factors on adults have been poorly explored in the previous Ethiopian study particularly in the study area. Objective: To assess prevalence and its associated factors of mortality after surgical treatment of bowel obstruction among adult patients at Debre Markos comprehensive specialized hospital, Northwest Ethiopia 2021 Methodology: - Institution based Cross sectional study design was used. A total 517 study participates was included by using consecutive sampling techniques from 23/02/2017 to 23/02/2021 at Debre Markos Comprehensive specialized Hospital. Data was collected from patient registration books and medical records available in the hospital by using checklists. Then data were entered to Epi data version 4.1 and exported to SPSS version 25 for analysis. A binary logistic regression model was fitted to identify factors associated with treatment outcome of bowel obstruction. P value less than 0.05 considered as significant in multivariable analysis Result: Among patients treated for bowel obstruction 70(13.5%) was died. Old age (>=55) ((AOR=3.70; 95% CI [1.02,3.39, p=0.046], Gangrenous large bowel (AOR 5.58; 95%CI [2.33, 3.36), p=0.0001].. prolonged hospital stay(AOR= 2.42; 95%CI [1.10, 5.55, p=0.043]). late presentation (AOR=2.84; 95% CI [1.33, 6.04]), comorbidity (AOR=3.79; 95%CI [(1.75, 8.21), p=0.001]), WBC(AOR=3.53 ;95% CI [(1.61, 7.70), P=0.002]). Low hemoglobin (AOR=3.50, 95%CI [(1, 62, 7.60), P=0.001]) was independent predicator of mortality.Conclusion: Mortality after surgical treatment of bowel obstruction were high and having gangrenous bowel, low hemoglobin level, late presentation, post-operative complications, leukocytosis and comorbidity was independent predicator of unfavorable outcomes. Give special care for patients treated with low hemoglobin, late presentation, having complications and leucocytosis. Create awareness to the public on advantage of early presentation to hospital.