This book constitutes of the proceedings from the 28th International Conference on Engineering of Complex Computer Systems, ICECCS 2024, held in Limassol, Cyprus, during June 19–21, 2024.  The 18 full papers and 4 short papers presented here were carefully reviewed and selected from 68 submissions. These papers have been categorized into the following sections: Machine Learning and Complex Systems; Neural Network Verification; A.I. for Software Engineering; Smart Contract; Formal Methods; Security & Program Analysis.