The Bulgarian greenhouse gas (GHG) emission profile reveals the energy sector as the most significant emission source and also as an area where great potential for GHG emissions reduction exists. Mitigation options in energy supply were selected considering the potential of fossil fuel substitution and new energy technology implementation in the context of the existing structure of energy system and projects for mid- and long-term development. Basically three modules of ENPEP were used : BALANCE - to calculate the energy flows and energy cost from primary fuel resources and fuel import to energy end-use, IMPACT - to calculate GHG emissions, and ELECTRIC - to project the electric system long-term development. Different mitigation measures combined in four scenarios were developed. The integrated mitigation scenario incorporated a mix : of mitigation measures in the energy demand and supply. Implementation of CO2 mitigation measures both in energy demand and energy supply would reduce the 2020 emission level by 34.3 Tg (29.1%), and by 544.2 Tg (21.7%) for the entire study period 2000 - 2020, compared to the baseline scenario.