The aim of this study was to investigate the effects of biochar produced from tropical biomass resources at different processing temperatures on methane production and rumen fermentation in vitro. Two available tropical biomass resources of rice husk and peanut shell were used for pyrolysis at three temperature levels of 300, 500 and 700^oC. Biochar was supplemented at 3% in diets of dry matter basis. In vitro fermentation characteristics and methane production were measured at 4, 24 and 48h after incubation. Results showed that there were no significant differences in terms of (i) gas and methane production, (ii) dry matter and organic matter digestibility (iii) pH and NH₃-N concentration between diets supplemented either rice husk or peanut shell drived biochar in an in vitro system (P>0.05). Whereas, different processing temperatures affected on total gas, production of methane and NH₃-N concentration (P<0.05), increasing processing temperature decreased methane production. There were no interactions between biomass resources and processing temperature on in vitro rumen fermentation and methane production. These results implicate that rice husk and peanut shell derived biochar produced at 700^oC can be used to mitigate methane emission from cattle production, further in vivo studies are required to confirm practical parameters.