In a radiological study of the pubic symphysis in 37 athletes (26 footballers and 11 others) and 156 young men as controls changes similar to those of osteitis pubis were found in 19 (76%) of the footballers and nine of the other athletes (81%) and 70 of the controls (45%). In the controls there was a significant correlation between their athletic ability and these changes.The clinical features consist of pain in the region of the pubis which may radiate to the groin or lower abdomen. Clicking may be present and indicates instability. Local tenderness is the only significant sign. Radiographs may show a combination of marginal irregularity, reactive sclerosis, and instability.A chronic stress lesion in the iliac component of a sacro-iliac joint was found in 20 out of 37 athletes, and 13 of them had instability at the pubic symphysis.It is concluded that repeated minor trauma is the primary aetiological factor. Though the radiological appearance may resemble that of osteitis pubis, there was no evidence that infection caused the lesion in this series. Spontaneous remission of symptoms is the most likely outcome. Rest from physical exertion is the most effective treatment, and stabilization of the pubic symphysis is indicated only rarely.