Recently leisure sports are gaining popularity. One of them is a golf. Golf population is about seven millions in Japan, nowadays. It is very good to participate in sports to keep up with our physical fitness. But it must be based on our physical strength. If we would like to make a rapid progress in the golf or feel pleasant with longer shot using a woody head club, there will be over burden and golfer's rib fracture may regut. The head of golf club makes centrifugal force, and we turn rapidly our body to gain more powerfull impact. If we play golf taking no account of our physical condition for longer time, for more than several days a week, these repeated stresses may be one of the cause of the golfer's rib fracture. At time, golfer (average golfer) vist our clinic complaining of pain in the chest, back, shoulder and neck. Though examination of these patients and physical sings and their progresses, we think that the methods of training of golf are not appropriate. Then we investigated the causes, mechanism and the character of golfer's rib fracture. In this parper we reported 12 cases of such fractures, we find, to my knowledge, 31 cases have been reported in Japan and only 3 cases in the world literature. But we do not think that this fracture is a rare one and many cases may be unnoticed to natural tendency toward rapid spontaneous healing.