Petroleum coke, a byproduct of the oil refining process is used as a source of energy given its high carbon content. The high ignition temperature and low volatile matter of petcoke poses combustion problems in a FBC boiler. This is sought to be mitigated by cofiring of biomass with coke. Biomass blends of 15% and 30% by weight of rice straw by weight have been used in this study. This paper presents the initial findings of a thermogravimetric analysis (TGA) done on petroleum coke and rice straw blends to evaluate their combustion characteristics. It is observed that the ignition time and temperature has been lowered and the reactivity of petcoke has increased resulting in better combustion characteristics in the presence of rice straw. The boiler thermal efficiency has also improved due to cofiring. © 2017 IEEE.