This book constitutes the refereed proceedings of the 4th International Conference on Digital Economy, ICDEc 2019, held in Beirut, Lebanon, in April 2019. The conference was founded in 2016 to discuss innovative research and projects related to the support role of Information System Technologies in the digital transformation process, business innovation and e-commerce. The 31 papers presented in this volume were carefully reviewed and selected from 89 submissions. The theme of ICDEc 2019 was "Digital Economy: Emerging Technologies and Business Innovation". The papers were organized in topical sections named: digital transformation; e-finance; social media communication; intelligent systems; e-commerce and business analytics; e-learning and cloud education; e-commerce and digital economy; data science; digital marketing; and digital business model.