In Hungary, gross emissions of carbon amount to some 17.6 millions t C per year. Forestry, the only sector which can offset emissions, seems to be a net sink of 1.6 Mt C per year. Afforesting large areas could substantially increase the carbon fixing capacity of the Hungarian forests. To assess the possibilities of sequestering carbon by afforestation, the CASFOR model, an adaptation of the COMAP model, was developed for Hungarian conditions. The technical potential scenario showed that, by afforesting 773,000 ha of former agricultural land by 2050, some 46 millions t C could be sequestered. The specific costs of sequestering carbon by afforestation are pretty low.