All raw natural gas needs conditioning. Polymeric membrane based gas separation processes, being cost and energy effective, environmentally friendly, as well as simple and versatile, have proven their potential as better alternatives to traditional processes for natural gas over the last three decades. In this article, the polymeric membrane based separation mechanisms for natural gas are analyzed. Two major membrane-based conditioning processes, acid gas removal from natural gas, and natural gas dehydration are presented. The current status, membrane material used, technological processes, limitations, and attractive approaches to overcome these limitations of these applications are discussed.