The use of biomass in iron and steelmaking as a reducing agent or as a source of energy has been identified as one of the possible solutions to reduce the fossil CO2 emissions for this carbon intensive industry. Despite the growing interest, there is very little knowledge concerning the CO2 emission reduction potential of using biomass-based fuels in iron and steelmaking processes. In this research, a life cycle CO2 analysis is made to compare life cycle CO2 emission profile of steel production in a Nordic integrated steel plant to different biomass scenarios in which pulverized coal injection to the blast furnace is partially or completely replaced with biomass-derived reducing agents. The system boundary is defined from cradle-to-gate and life cycle inventory is made by combining traditional life cycle modeling practices with process modeling done by sophisticated BF energy and mass balance model.