This book constitutes the refereed conference proceedings of the 6th International Conference on Mining Intelligence and Knowledge Exploration, MIKE 2018, held in Cluj-Napoca, Romania, in December 2018.  The 33 full papers presented were carefully reviewed and selected from 93 submissions. The papers were grouped into various subtopics including evolutionary computation, knowledge exploration in IoT, artificial intelligence, machine learning, image processing, pattern recognition, speech processing, information retrieval, natural language processing, social network analysis, security, and fuzzy rough sets.