Objective: To investigate the prevalence of osteochondrosis in children and adolescent soccer players. Materials and Methods: A questionnaire was distributed to players of all 113 junior soccer teams participating in a regional summer championship in August 2012 inquiring about pain in the body during or after training or a match. Physical examination of the lumbar spine or legs was recommended to players who complained of pain on the questionnaire, and for those who had positive findings on the physical examination, radiographic or ultrasonic examination at our hospital was recommended. Results: Questionnaires were collected from 1162 players of 97 teams, and 547 players (47.1%) complained of pain in the lumbar spine or legs. Physical examination was performed on 494 players, 394 of whom were referred for physical examination (79.8%). Of these 494 players, 20 (4.0%) had positive lumbar spine findings, 26 (5.3%) had hip findings, 198 (40.1%) had knee findings, 117 (23.7%) had ankle findings, 226 (45.7%) had heel findings, and 90 had findings in other parts of foot (18.2%). Radiographic or ultrasonic examination was performed in 106 (26.9%) players at our hospital and 80 (75.5%) players were diagnosed with osteochondrosis. Sever's disease was diagnosed in 49 players, Osgood-Schlatter disease in 13, bipartite patella was in 12, Sinding-Larsen-Johansson disease in 10, osteochondritis dissecans of the distal femur in 1, and spondylolysis in 3. Conclusions: The majority of players who had experienced pain and were found to have osteochondrosis had severe injuries such as osteochondritis dissecans or lumbar spondylolysis. We suggest many of the players involved in this study receive further radiographic or ultrasonic examination. J. Med. Invest. 61: 369-373, August, 2014