Clinical laboratories are identified as one of the most important and expensive units of the health system. Therefore, it is essential to pay attention to these units' cost efficiency. This study purpose was to evaluate the economic efficiency of hospitals' laboratory units affiliated to Urmia University of Medical Sciences (UMSU), in order to assess their performance.This research was a descriptive-analytic study that was accomplished in 2017. The statistical population of the study included all of the hospitals' clinical laboratories affiliated to UMSU. Moreover, DEA method and Deap software were used to analyze data. In this study, technical and allocative efficiencies of the studied laboratory units were also calculated in addition to the determination of the economic efficiency of the laboratories.The average economic efficiency of clinical laboratories calculated by DEA in 2017 was 0.676. This value was lower than the allocative and technical efficiency scores, which indicates that these units could attain full efficiency by reducing their costs without having any effect on output values. Moreover, about 14 percent of the clinical laboratory units were economically efficient. In addition, it is noteworthy to state that, from total of university hospital laboratories, only three hospitals had no economic excess or deficiency values of inputs.Considering that 76% of laboratory units have not been economically efficient, it is necessary for the laboratory managers to consider optimum allocating of resources, with respect to the cost of laboratory equipment and inputs in order to increase their units' economic efficiency.