The aim of the present work is to determine the validity of the Net-PromoterScore for measuring loyalty and to compare two relational models which incorporate the dimensions of quality, value, satisfaction and loyalty. Firstly, convergent validity of the Net Promoter Score in sport service users was determined through correlational analysis of both instruments. Following this, the two models were tested using, first, the Net-Promoter-Score and, second, a multidimensional scale that measures future intentions. In both cases, the same instrument was used to evaluate quality, value and satisfaction. A confirmatory factorial analysis was conducted of the studied models with the objective of testing the stability of the models. The results obtained demonstrate that the two instruments are valid for measuring the loyalty of sport service users. Further, findings show that the model using the multidimensional scale provides more information to guide the decision making of those responsible for the management of these services.