Previously established and validated coal combustion model in a circulating fluidized bed (CFB) was employed to predict co-combustion of lignite and biomass processes. The validity of the model was successfully performed on a large-scale 261 MWe COMPACT CFB boiler. Forest biomass, sunflower husk, willow and lignite coal were applied in co-combustion tests with different shares of biomass and lignite. The energy fraction of biomass in fuel blend was: 7%, 10% and 15%. Emissions of CO2, CO, SO2 and NO (i.e., NO + NO2) from the co-combustion tests, measured during experiments and predicted by model were compared. The gaseous pollutant emissions, evaluated using the developed model were in a good agreement with experimental results. (C) 2013 Elsevier B.V. All rights reserved.