Abstract: Because of potential benefits of Demand Side Management (DSM) at operation, economic and environmental levels, DSM is introduced as the first choice in all energy policy decisions. Under deregulation, the DSM programs have been expanded to include Demand Response Programs (DRPs). In the present study, in order to investigate effect of changes in DRPs on the emission level of thermal power plants and Supply Side Resources (SSRs) profit, an appropriate model of Unit Commitment (UC) problem incorporating Demand Side Resources (DSRs) with implementation of Time Based Rate (TBR) programs of DRPs (UC-DSRs with TBR programs) is presented and studied. The proposed model is applied to determine the optimal TBR program with the aim of lowest emission. In the other word, the amount of emission per day in UC-DSRs problem is used to prioritize the TBR programs from ISO’s point of view.