When alluding to quality it is not only referring to goods, but also to service, but in this case quality is intangible. These are personal experiences of clients with a company’s employee. Due to interest showed by companies to accomplish quality and needs of costumers related to the service offered, surged the demand of defining the term “quality service”. (Llorens y Fuentes, 2000). A quality service is not only “adjust to specifications”, but to adjust to the needs of the clients. There is a vast difference between the first and the second perspective. Service organizations that make mistakes with their clients, no matter how fast the service is done, they are not offering a quality service. (Berry, Bennett and Brown. 1989). On the other hand, Standard ISO 9001:2008 defines client’s satisfaction as the perception it has about the grade in which they requirements have been accomplished. Therefore, excellent companies have to measure their performance according to their competitors; as well as the best companies that employs the same productive or administration processes, establishing clients’ perception about their products and services and if they are really satisfied or not. The purpose of this empiric investigation consisted in evaluating service quality to determine the satisfaction of Agencia Fiscal del Estado clients, specifically in the taxes collection area, through the application of SERVQUAL method, intending to expose a useful tool to quantify client’s satisfaction; to perceive the difference between the previous expectations and the appreciation of the service offered. For the evaluation of quality service in Agencia Fiscal del Estado, in the taxes collection area, the method was supported with a questionnaire based in SERVQUAL to determine the quality satisfaction level in the service offered to their clients. First, the questionnaires were adapted to each of the areas to measure; next a pilot test to continue with deciding the size of the portion, frequency of application of the questionnaire, already validated by the investigation team, and finally, interpretation of the results obtained.