During a collaborative review at three institutions, we documented 19 cases of stress fractures of the ribs in golfers. There were 13 men and 6 women with an average age of 39 years (range, 29 to 51). The 4th to 6th ribs were the most commonly injured. All fractures occurred along the posterolateral aspect of the ribs, and nine patients had fractures in more than one rib. Sixteen golfers sustained injury on the leading arm side of the trunk. Eighteen golfers were beginners, and the one experienced golfer had dramatically increased his practice time on the driving range before injury. Plain radiographs were usually diagnostic. However, bone scintigraphy was necessary to reach a diagnosis in three cases. A delay in diagnosis of 6 to 8 months occurred in two cases that were originally misdiagnosed as back strains. Stress fractures of the ribs in golfers may be more common than previously realized and may be incorrectly diagnosed as recalcitrant back strains. Based on the findings of other studies, we think fatigue of the serratus anterior is the mechanism of injury. We recommend strengthening the serratus anterior as rehabilitation after this injury and in a general conditioning program for golfers.