Six cases of nasal septum perforation were found among welders during periodic physical checkup in 1997. Considering the size, shape and margin, the perforations were assumed to have been occurred several years before of which the diameter were 8~15 mm. To investigate the cause of perforation, we reviewed the past history of preemployment, the results of annual working environment survey and the material safety data sheets of welding rods and steels with which they have dealt, and analyzed the concentration of several metals of welding fume and the concentration of blood and urinary chromium. In the result, we presupposed that the nasal septum perforations of welders were due to chronic exposure to low level hexavalent chromium and/or nickel, and report these cases with literatures review.