Public organization, especially for The Large Taxpayer Office I which is playing role as the pilot project for the coming period of Tax Service Office, is acclaimed to give the effective, efficient and cooperative service performance and also satisfaction oriented for the taxpayers as the subject.This research is trying in focusing the Account Representative service effectiveness at The Large Taxpayer Office I by analyzing a number of factors which are influence the quality of services in order to catch the target especially for The Large Taxpayer Office l and generally for Directorate General of Taxes.The target of this research in intended to know the quality of service given by Account Representative which is evaluated from the aspect of taxpayer's satisfaction (perception and expectation of the taxpayer).In order to measure that quality of service, the concept and theory of Zeitaml-Parasuraman-Berry is used by giving indicators of size measurement of customer's satisfaction (taxpayer) which are consisted of five dimensions : Tangibles, Reliability, Responsiveness, Assurance and Empathy The analytical descriptive survey method is used in this research by trying to analyze and to take conclusions the recent problems based in data, facts and information deal with.In this research, the conclusion that quality of service of the Account Representative at The Large Taxpayer Office I has not earned yet to give service gratifying as expected by a taxpayer. Therefore, the Account Representative have to be more improve the quality of its service to the taxpayer seriously, and finally the organizational effectiveness at The Large Taxpayer Office I can be reached.