The Proceedings of the 1st Workshop on Modeling and Simulation of Software-Intensive Systems (MSSiS 2019) bring the papers selected and presented in the edition of the event held in Salvador, Brazil on September 25, 2019. In this issue, the proceedings include eight full papers and two short papers, besides one full invited paper. These papers were selected through a double blind peer review process, from a total of 14 full papers, which implied an acceptance rate of 57.1% for full papers. The event's program committee was coordinated by Valdemar Vicente Graciano Neto (UFG), Elisa Yumi Nakagawa (USP) e Bernard Zeigler (Universidade do Arizona), who organized this volume. The articles in this volume were submitted on July 19, 2019, accepted for publication on August 07, 2019, with the final version submitted on August 14, 2019.

For more information about MSSiS 2019, visit the event's website.