Background: postoperative pain is a confluence of somatic, sensory and psychological responses to surgical injury. The annual number of surgical operations performed is increasing in our country; with this rise in number of surgeries performed effective assessment and management of postoperative pain is becoming a challenge. Inadequate assessment and management of postoperative pain will result in suffering, increased risk of morbidity and mortality, longer stay in hospital and economic burden. In Ethiopia there are scanty data available to characterize the severity of postoperative pain and its predictors Objective: To assess severity and Risk factors that contributes to post-operative pain among operated orthopedic cases in Tibebe Ghion Specialized Hospital Method: A hospital based cross sectional study design was conducted in Tibebe Ghion Specialized Hospital orthopedic ward for a patient stayed hospital for at least 24 hour after surgery from November 15 to December 15 2020. Sample size calculated using Cochran sample size formula. Assuming the prevalence of post-operative pain of 78%, with 95% confidence level and 5% precision, the calculated sample size was 96. Data collected using questionnaire via interview and reviewing the patients chart after taking consent. The collected data was cleaned manually for completeness, and analyzed using SPSS version 26 and descriptive statistics such as mean, percentage and standard deviation determined to describe the data. Numeric rating scale was used to assess pain severity. Binary logistic regression analysis was used to identify factors associated with postoperative pain.. Result: A total of 96 patient age 18 year and above were used to assess postoperative pain severity, out of which 41.7% patients have no feeling of pain at 2hours of surgery but 34.4% were having moderate to severe pain. Most of the patient‘s pain intensity increases after two hours of surgery.75% and 72.9% patients have moderate to severe pain at 12 and 24hours of surgery respectively. Conclusion: The finding of this study suggests that post-operative pain severity is still high and was not effectively managed. Identifying perioperative factors for the occurrence of moderate/severe post-operative pain may be useful for designing factor specific interventions.