This book contains revised selected papers from the 17th International Conference on Membrane Computing, CMC 2017, held in Milan, Italy, in July 2016. The 19 full papers presented in this volume were carefully reviewed and selected from 28 submissions. They deal with membrane computing (P systems theory), an area of copmputer science aiming to abstract computing ideas and models from the structure and the functioning of living cells, as well as from the way the cells are organized in tissues or higher order structures. The volume also contains 3 invited talks in full-paper length. .