PURPOSE: To evaluate and analyse the operative results of reconstruction of medial collateral ligament(MCL) in old posterior dislocation of the elbow. MATERIALS AND METHODS: Nine patients (from 1989 to 1999) with old posterior dislocation of the elbow treated by operation were reviewed. We analysed the pattern of dislocation, associated injury, method of operation, complication and functional results. All patients were treated with open reduction. Reconstruction of MCL was undertaken in three patients of nine. RESULTS: All nine patients who had underwent open reduction were improved in the flexion-extension motion of elbow. Three patients of nine underwent reconstructive surgery of MCL were much improved in the flexion-extension motion. But there is no differences in improving the pronation-supination motion between of them(P>0.05, ttest). CONCLUSION: Precise understanding of MCL anatomy and appropriate intraoperative technique are mandatory. We achieved much more range of motion in the cases of reconstruction and early motion rather than those of immobilization for 3 weeks with K-wire. We believe reconstruction of MCL is a useful addition to treatment options for old elbow dislocation of elbow.