We selected one hundred magnetic resonance imaging(MRI) in knees of patients with internal derangement of the knee, in all of those cases, arthroscopic operations were performed. Twenty medical doctors, who didnt know the arthroscopic findings, reviewed these MRI; 5 radiology specialists, 5 radiology residents, 5 orthopedic surgeons and 5 orthopedic residents. The radiologists were not informed about the medical history and physical examination of the patients when they read the MRI, but the orthopedic surgeons had the information about those of the patients. The accuracy of reading of MRI was compared between radiologists and orthopedic surgeons, and between specialists and residents. The check-list of the reading were medial and lateral meniscus, ACL and PCL, medial synovial plica and osteochondral lesion. Overall results of accuracy of MRI reading were as follows; radiology specialist-86%-, radiology resident-77%-, orthopedic surgeon-90%- and orthopedic resident-84%-. So accuracy was superior in orthopedic group and specialist group. The medical history and the physical examination of the patients were very helpful to improve accuracy of MRI reading. Reading skill was also important for accurate reading of MRI.