Objective: The aim of this study is to analyze the cost spent on databases in Yazd University and compare it with the amount of use of the resources by users Methodology: A survey has been conducted. The cost - benefit analysis of Science Direct, ProQuest and EBSCO has been calculated by securing financial information about the subscription fee, and the numbers of articles have been downloaded in 2009.Findings: The cost - benefit of the three databases, respectively, are 65, 814, 21, 572, 6, 653 Rials.29.24% of all publications in Science Direct haven’t been used at all. In terms of the frequency of use, only 2 of the 7 subset of EBSCO have been used more heavily.53/34% of the total articles from ProQuestare covered in one of its subsets.The databases are ranked based on their cost - benefit is Science Direct, ProQuest, and EBSCO