The paper presents the results of studies on methane fermentation of chicken manure. The study was conducted in a reactor with effective volume of 3 liters, working in semicontinuous mode. Hydraulic retention time was 10 days, and total solids content of substrate — 10 %. The temperature was maintained at 50 °C. The content of the reactor was mixed with a mechanical stirrer with rotation frequency 38.4 rpm. for 15 minutes every hour. Methane fermentation took place with an average pH of 8.1, the concentration of ammonium nitrogen — 3880 mg/l and free ammonia — 1035 mg/l. As a result of microbial community adaptation to high concentration of ammonia nitrogen, the production of 2.62 l/l (262 ml/g TS) biogas with methane content of 58 % was achieved.