If you become a Realtor then you will automatically become a member of the NAR. You can become a real estate agent without becoming a Realtor but if you want to be able to use the MLS, and be a member of the local MLS association, they will typically require that you become a Realtor. A Realtor is bound by the code of ethics which is a required class all Realtors must take and it must be renewed every four years in order to maintain the Realtor designation. A real estate salesperson or agent/broker can perform real estate related work but they cannot hold themselves out as a Realtor unless they have taken the code of ethics coursework and become a member of the local, state and national Realtor associations.