BACKGROUND: Recalcitrant fracture non-union is a condition that is difficult to treat and may require multiple surgeries, sometimes requiring treatment with periosteal flaps. The use of periosteal flaps can be preferred for the treatment of non-unions that do not yet have extensive bone defects. This study aims to share our experience with medial femoral condyle periosteal flap for the treatment of recalcitrant non-union in long bones of the upper limb. METHODS: Seven patients who underwent treatment for upper limb non-union with a free medial femoral condyle periosteal flap between 2015 and 2019 were retrospectively evaluated. Patients who had previously underwent implant revision and non-vascular grafting procedures and with failed atrophic non-union were included in the study. Non-union was in the humerus in two patients, ulna in three, radius in one, and clavicula in one patient. Demographic data, non-union features, complications, and radiographic findings of the patients were evaluated. Functional results were evaluated according to Quick Disabilities of Arm, Shoulder, and Hand (Q-DASH) scores. RESULTS: Mean patient age was 41 (23–60) years and the mean follow-up time was 33 months (16–56). Non-union time ranged from 9 to 24 months. Additional surgical procedures were not required. One patient developed a hematoma in the donor site and required surgical drainage. Medial collateral ligament injury of the knee occurred in one patient. Union was observed in all patients in an average of 3 (2–7) months. Mean pre-operative Quick Disabilities of Arm, Shoulder, and Hand (Q-DASH) score was 56 (33–95), while mean post-operative control Q-DASH score was 5 (0–33); the improvement was statistically significant (p=0.017). The functional outcomes of all patients improved, as confirmed by Q-DASH score. CONCLUSION: The medial femoral condyle periosteal flap offers a viable treatment option for recalcitrant non-unions. This flap has low comorbidity compared to other flaps and is a feasible option for revascularization and bone formation in atrophic non-unions.