Background: In evaluating the activities and performance of radiology units, the main aim of applying feasible scientific methods is to use technological and human resources optimally. One of the suitable scientific methods in this field is determining the technical, economic, and allocative efficacy of these centers. We aimed to assess the economic efficiency of radiology units of hospitals affiliated to Shiraz University of Medical Sciences, southern Iran. Methods: In this descriptive-analytical cross-sectional study, the technical, economical, and allocative efficiency of 27 radiology units of public hospitals was assessed using data envelopment analysis. The input oriented envelopment form with the assumption of the varied outputs with respect to the scale was used. Related forms were filled using the existing information in the archives of radiology centers. Input variables in this study were the number of radiology devices, the number of expert personnel, the number of technicians, equipment maintenance and depreciation costs, and the salaries of the experts and technician. Output variables included the number of admitted patients and the number of photographic film. Then, data were analyzed using the DEAP software for calculating the various forms of efficiency. Results: The mean scores of economic, technical, and allocative efficiencies of radiology units were 0.749, 0.880, and 0.852, respectively. The final score of economical efficiency was lower than the technical and allocative efficiency scores. Only 15% of radiology units were economically efficient. Conclusion: Economical efficiency can be attained when resources are used in the best possible way and not wasted. Therefore, a combination of inputs that comprise the lowest costs should be selected.