Two patients of unusual cough related stress fractures of the ribs are presented. Both patients complained of cough and chest pain with respiratory infection, and the initial chest radiographs showed only an infiltrative shadow due to bronchopneumonia in the lung field, however, failed to reveal any definite osseous abnormality of the ribs. Follow up chest radiographs revealed a callus formation in the fracture sites. In both patients, fracture sites were multiple and located at the axillary line, and radionuclide bone scan disclosed focal abnormal concentrations of activity in these characteristic locations of the lesions. Moreover, there were abnormal accumulation sites in the adjacent above and below ribs, and this finding also seemed to be characteristic of cough related stress fractures of the ribs.