This volume LNCS constitutes the refereed proceedings of the 19th International Conference on Integrated Formal Methods, IFM 2024, during 13-15 November 2024, held in Manchester, UK. The 19 full papers presented in this volume were carefully reviewed and selected from 58 submissions. The conference focuses on all aspects of the design of integrated techniques, including language design, verification and validation, automated tool support, and the use of such techniques in software engineering practice.