This book presents key advances in intelligent information technologies for industry. This book of Lecture Notes in Networks and Systems contains the papers presented in the main track of IITI 2021, the Fifth International Scientific Conference on Intelligent Information Technologies for Industry held on September 30 - October 4, 2021 in Sirius, Russia. The conference was jointly co-organized by Rostov State Transport University (Russia) and VŠB-Technical University of Ostrava (Czech Republic) with the participation of Russian Association for Artificial Intelligence (RAAI) and Sirius University (Russia). IITI 2021 was devoted to practical models and industrial applications related to intelligent information systems. It was considered as a meeting point for researchers and practitioners to enable the implementation of advanced information technologies into various industries. Nevertheless, some theoretical talks concerning the state of the art in intelligent systems and soft computing were also included into proceedings. There were 180 paper submissions from 14 countries. Each submission was reviewed by at least three chairs or PC members. We accepted 69 regular papers (38\%). Unfortunately, due to limitations of conference topics and edited volumes, the Program Committee was forced to reject some interesting papers, which did not satisfy these topics or publisher requirements. We would like to thank all authors and reviewers for their work and valuable contributions. The friendly and welcoming attitude of conference supporters and contributors made this event a success!