This book presents the proceedings of the 3rd Conference on Computer Science, Electronics, and Industrial Engineering (CSEI 2021), held in Ambato in October 2021, with participants from 10 countries and guest speakers from Chile, Colombia, Brasil, Spain, Portugal, and United States. Featuring 20 peer-reviewed papers, it discusses topics such as the use of metaheuristics for non-deterministic problem solutions, software architectures for supporting e-government initiatives, and the use of electronics in e-learning and industrial environments. It also includes contributions illustrating how new approaches to these converging research areas are impacting the development of human societies around the world. As such, it is a valuable resource for scholars and practitioners alike.