This article examines the process of evaluating the integral index of the software quality using the method of fuzzy aggregation of multiple private indicators. The aim of the study is to determine the applicability of this approach in practice and research of its formalization and algorithmization approaches. A set of aggregation algorithms in the fuzzy inference model was used and their comparison in the application to the given problem is provided. Various modifications of the standard algorithm of fuzzy inference using fuzzy set operators, as well as different kinds of norms and conforms are considered. The study has revealed a wide variation of aggregation methods and provided the method of selecting the optimal one based on the comparison with standard numerical grades. The applicability of the methods of fuzzy logic was shown in the mathematical explanation of the decision making process, opening up the possibility of fuzzy-linguistic description of the subject area, private alternatives indicators and target vector formalizing.