ABSTRACT: Background: Ankle arthrodesis is major surgery need good experience. Decision of ankle fusion should be taken after exhaustion of the all other treatments methods. We aimed to evaluate the function and radiological outcome of patients with ankle arthrodesis who are operated upon in Zagazig university hospitals for post-traumatic ankle arthritis. Patients and methods: 18 patients ranging from 26 to 60 years suffering from posttraumatic ankle arthritis were included and underwent Trans fibular Ankle Arthrodesis with Rigid Internal Fixation. Patients followed up post- operatively in outpatient clinic according to their planned visits for assessment of functional and radiological outcomes. Assessment of functional outcomes and pain was done through American Orthopedic Foot and Ankle Society (AOFAS) scale. Results: The mean Preoperative AOFAS score was 46.89 (±3.69 SD) with range (40-52) while the mean Postoperative AOFAS was 74.44 (±10.20 SD) with range (56-90).There were 5 (27.8%) with moderate pain and 13 (72.2%) with severe pain while post-operatively there were 5 (27.8%) with no pain, 10 (55.6%) with mild pain, 1 (5.6%) with moderate pain and 2 (11.1%) with severe pain. There were 15 (83.3%) with average healing time (12 weeks) and 3 (16.7%) were delayed (12-24 weeks). According to complications, there was 1 (5.6%) case with Wound sepsis, 1 (5.6%) with Post-operative deformity and 2 (11.1%) were Non-union. Conclusion: Ankle arthrodesis is gold standard operation for late stage painful ankle arthritis in well planned and selected patients.Trans fibular ankle arthrodesis achieves a high rate of union and good functional outcome on follow up.