Membrane technology for gas separation applications was commercialized about three decades ago for natural gas upgrading and nitrogen blanketing purposes, in particular, using a limited number of polymer materials such as polysulfone, cellulose acetate, and polyimide. There are still many opportunities for the development of new polymer membrane materials for gas separation applications as the separation performance of existing membrane materials should be improved. In this review, we introduce the research progress on the recent development of high performance gas separation membranes for CO 2 separation applications.