© 2020 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.In this study, biogas production was carried out from apple pulp (EP), orange pulp (PP) and chicken manure (TG) mixtures under anaerobic working conditions. Operating temperature (outside temperature) was selected as 40̊C for all experiments. The dry matter content was taken as 10 % by mass for all experiments. In the first stage of anaerobic digestion experiments, optimum mixture ratios were determined. The reactor where the highest biogas production was 215 ml / g UK for EP:PP:TG values prepared in different ratios was determined as the optimum reactor. In this reactor the mixture ratio of EP:PP:TG by mass was determined as 1:1:3. Thermal pretreatments were applied to this optimum reactor at temperatures of 100 and 120°C and 30, 60 and 90 min for each temperature. The highest biogas production as a result of 100°C thermal pretreatment was 338 ml / g VS and 368 ml / g VS at 120°C thermal pretreatment. Biogas production was controlled by measuring the removal of soluble chemical oxygen demand (SCOD). The highest SCOD removal in the untreated reactor was 58%, while the highest SCOD removal in the 100°C and 120°C thermal pretreated reactors was 85.1% and 92.9%, respectively.