This book constitutes the refereed post-conference proceedings of the Third EAI International Conference on Innovations and Interdisciplinary Solutions for Underserved Areas, InterSol 2019, and the 8^th Conference on Research in Computer Science and its Applications, CNRIA 2019, held in Saint-Louis, Senegal, in April 2019. The 16 papers presented were selected from 34 submissions and issue different problems in underserved and unserved areas. They face problems in almost all sectors such as energy, water, communication, climate, food, education, transportation, social development, and economic growth.