The paper analyses profitability of biogas production in livestock farms in Poland with a focus on micro-biogas plants. Due to the high value of investments a crucial issue, from the farmers’ point of view, is the mechanism of financial support. The efficiency of investments has been measured assuming three variants of power of CHP plants. In addition, two scenarios of financial support have been taken into consideration: the “old” mechanism of green certificates and a forthcoming mechanism based on the new Act on Renewable Energy Resources. The new system introduces feed-in tariffs for small plants and auctions and guarantees of purchase for larger biogas plants. The results of the analyses indicate a strong dependence of the financial effects of micro-biogas plants on subsidies. It can be concluded that, under the current state of market development and financial support offered to micro-scale biogas production, investments in biogas plants are in general unprofitable.