Evaluation of service quality of public hospitals has been largely ignored by health care providers although it is vital for human life. For this, some regulations are being done by Turkish Ministry of Health to improve service quality. One of them is to construct quality teams for hospitals. The other is classification of hospitals into five groups based on their service quality and government provides promotion to hospitals based on this classifications. However, the current classification procedure is not based on an analytical method. Therefore, in the scope of this paper, service quality index has been developed in order to present a scientific basis for classification of hospitals by using multiple criteria decision making tools with respect to existing parameters in the literature. In the scope of this study, service quality parameters are determined and importance degrees of them are obtained by using analytic hierarchy process in terms of service providers and patients. Then, a formulation has been provided to obtain service quality index (SQI) for hospitals. A case study for public hospitals is presented to test applicability of the proposed method.