According to propositions put forward by the scientists and practicians, the quality of services is supposed to influence the financial performance. However, this relationship requires empirical verification consisting not only in confirmation of the existence of such a relationship but also in defining its strength and the factors (dimensions) permitting to achieve both a proper level of the service quality and the financial effectiveness. The objective of the paper is to make a world-wide review of the most interesting investigations that have used non-parametric methods (in the first place the Data Envelopment Analysis) for quantitativemeasurement of the quality of financial services and their impact on the effectiveness. The application of non-parametric methods covers all kinds of research, fromthemost simple input of variables representing the quality of financial services into the operating efficiency analyses up to the input.output models referring to the quality efficiency alone. Apart from publications using data from banking institutions, the paper also covers the investigations that have used non-parametric methods in other sectors of services, but can easily be adapted to the conditions typical of the financial services.