[INTRODUCTION] The purpose of this study was to present the effect of case report on rehabilitation exercise program after multiple drilling and debridement from osteochondritis dissecans(OCD) of femur. [METHOD] A case was a badminton player had been multiple drilling on lateral femoral condyle. She is 12 years old. She have been felt pain since 2010, but she did still kept playing badminton. She went orthopedic clinic and prescribed medicine and physical therapy by physician. However, She felt more painful knee when she went up and down, or knee was flexed. So, She visited in office of clinical exercise professional. The result of physical examination was positive from patellar compression test and She had swelling, crepitus and locking. CEP referred the patient to orthopedic doctor for surgery. MRI view showed OCD. She had been surgery of multiple drilling and debridement. She received exercise rehabilitation after surgery. [RESULT] The result of exercise rehabilitation was restored to 118 degree of active range of motion and 125 degree of passive range of motion at 3 week after surgery. Range of motion was restored to within normal limit at 6 week after surgery. The size of injuried cartilage was 14mm×8mm and after surgery improved 8mm×7mm in frontal MRI view. Also, Sagittal MRI view showed injuried cartilage was decreased from 31mm to 21mm. But depth of injuried cartilage was so thin. [CONCLUSION] The rehabilitation exercise program after multiple drilling and debridement from OCD on lateral femoral condyle should be started from 1 week after surgery and must be increased exercise intensity step by step. Especially, Proprioceptive exercise started initially, and increased strengthen exercise to full weight bearing. All exercise intensity should be checked pain scale below 3.