Purpose: This study is to evaluate the clinical results of pull-out suture for root tear of posterior horn of medial meniscus. Materials and Methods: Between March 2006 and February 2011, We studied 40 cases with the root tear of posterior horn of medial meniscus which follow up more than 1 years. Mean age was 49.5 years old. We excluded osteoarthritis or varus deformity patients more than 5 degrees. pull-out suture was performed to the patients with grade 0-2 of Kellgren and Lawrence classification. According to Outerbridge classification, evaluation of cartilage damage was performed during arthroscopy. Evaluation of clinical result was used the Lysholm score. Results: The mean pre-operation Lysholm score was 63.9 and post-operation score was 86.3. The complete failure rate was 3 of 40 cases (7.5%). Twenty of 40 cases (50%) showed cartilage lesions in weight bearing portion of medial femoral condyle which were 12 cases in grade 1, 5 cases in grade 2 and 3 cases in grade 3 according to the Outerbridge classification. Conclusion: In the treatment of pull-out suture for root tear of posterior horn of medial meniscus, exclusion of more than moderate arthritis or varus deformity is very importment. Pull-out suture seems to be a useful treatment of the root tear of posterior horn of medial meniscus in mild osteoarthritis or varus deformity of middle ages.