Rationale and Objectives. The authors investigate the effect of image processing on diagnostic performance in the reading of computed chest radiographs. Materials and Methods. Six radiologists read 168 chest images with and without the use of image processing. Diagnostic performance was measured by means of reviewer operating characteristic analysis, and changes made in diagnostic decisions with the use of image processing were evaluated. Results. There were no statistically significant differences between reader performance with image processing and reader performance without image processing (P < .05). Readers' decisions were just as likely to change from false-negative to true-positive as from true-positive to false-negative with the use of image processing. More decisions changed from true-negative to false-positive than from false-positive to true-negative with processing. Conclusion. The effect of image processing does not greatly influence diagnostic performance in chest radiography.