The motivation for this study is the disagreement of statistical and literature data about potential quantities of biomass in Serbia. This difference is mainly caused by changed status in practice due to several reasons: changes in ownership caused by transition, different application of technologies in practices, organization of work and economic reasons. The main aim is to precisely establish sorts and amounts of organic biomass in Serbia that can be transformed into heat and electricity. So far, data about the quantities of biomass residues in agriculture, forestry and communal services have been collected and published. Data collection methods are different and generally based on statistical data. The paper explains in detail methods of data collection and processing of crop production, fruit growing and viticulture, livestock, forestry and communal services. On the basis of precise data collection, it has been established that there are 26.3 million tons of biomass residue in Serbia every year. The total amount of biomass is reduced by 20-30% in relation to the period of 10 and more years ago. On the basis of the situation in agriculture and forest production in Serbia, it is estimated that out of the total amount of biomass, some 30-40% can be used for the production of heat energy, electricity and biofuel. The remaining biomass can be used in order to increase soil fertility, as cattle spread, for vegetable production, means for polishing in metal industry, for insulation in civil engineering, in cosmetics industry, production of animal feed, and so on.