Background: ELBOW stiffness is a debilitating condition with different etiologies including trauma, head injury, and burns, which seriously interferes with the patient’ s daily activities. Objectives: Here, we aimed to report the outcome of ELBOW release surgery in patients with ELBOW stiffness caused by different etiologies. Methods: In a retrospective study, the outcome of surgery was evaluated in 18 patients with ELBOW stiffness. The indication for surgery was the functional loss of ELBOW range of motion that failed at least six months of conservative management. ELBOW range of motion was evaluated before and after the surgery. Mayo ELBOW performance score (MEPS) was used to assess ELBOW function at the final follow-up session. Results: The mean follow-up period of the patients was 4. 5 2. 6 years, ranging from 2 to 10 years. The etiology of stiffness was trauma in 11 cases, central nervous system injury in six patients, and burns in one patient. The mean pre-operative supination, pronation, and flexion arc improved by 15. 3° , 20. 9° , and 62. 2° at the final follow-up evaluation, respectively (P = 0. 028, P = 0. 008, and P < 0. 001, respectively). The mean MEPS of the patients was 85 9. 1, ranging from 65 to 95. According to the MEPS scores, the functional outcome was excellent in 8 (44. 4%) patients, good in 7 (38. 9%) patients, and fair in 3 (16. 7%) patients. Conclusions: The release of stiff ELBOW could be regarded as an effective treatment that provides an acceptable gain in the range of motion and considerable improvement of ELBOW function.