This book constitutes the proceedings of the 5th International Conference on Decision Support Systems Technologies, ICDSST 2019, held in Madeira, Portugal, in May 2019. This year the conference is a EURO mini conference and therefore has a slightly different acronym: "Em C-ICDSST 2019".The EWG-DSS series of International Conference on Decision Support System Technology (ICDSST), starting with ICDSST 2015 in Belgrade, was planned to consolidate the tradition of annual events organized by the EWG-DSS in offering a platform for European and international DSS communities, comprising the academic and industrial sectors, to present state-of-the-art DSS research and developments, to discuss current challenges that surround decision-making processes, to exchange ideas about realistic and innovative solutions, and to co-develop potential business opportunities.The main topic of this year s conference was Main Developments and Future Trends . The 11 papers presented in this volume were carefully reviewed and selected from 59 submissions. They were organized in topical sections named: decision support systems in societal issues; decision support systems in industrial and business applications; and advances in decision support systems methods and technologies.