To help curb excessive radiography, we developed a protocol for selecting patients with injured extremities who need x-ray examination, and we tested the protocol prospectively in 848 patients to determine its safety and effectiveness. Strict adherence to the protocol would have reduced x-ray usage by 12 per cent for upper extremities and 19 per cent for lower extremities. The actual reductions were 5 per cent and 16 per cent, respectively, since further reductions were limited by patient's demands for x-ray examinations. One fracture in 287 were missed, but the treatment was appropriate and the outcome satisfactory. By eliminating superfluous x-ray procedures, the protocol could reduce charges by $79 million to $139 million nationwide, without compromising quality of care or increasing malpractice liability. Nevertheless, even the best protocol cannot eliminate all negative x-ray studies. These results should serve as a stimulus for judicious use of radiography, but also as a warning to avoid overzealous cost-containment strategies that would reduce x-ray usage to below a safe threshold.