We performed computed tomography (CT) of the nose and paranasal sinuses in 21 patients with chromium induced septal perforation or thinning. Twenty patients showed various magnitudes of septal perforation. Twelve of 20 had perforation at the mid portion of the cartilaginous nasal septum. One patient had a sheet-like thinning of septal cartilage. Sixteen patients had mucosal thinning of the nasal conchas. In most cases, unilateral involvement of the inferior concha was seen. Eleven of 21 cases showed paranasal sinus mucosal thickening and one patient had a cyst or polyp in the sinus cavity. The main finding was nodular thickening of mucosa. Septal perforation by inhalation of chromic acid was located in the cartilaginous septum and there was no destruction of the bony septum and wall of the sinuses.