This study deals with the effect of different biomass fuels on the combustion process of an advanced micro-gasifier stove. Agricultural wastes from tamarind seed are proposed as a source of energy and their thermochemical properties are analyzed and compared with coconut shells and Prosopis juliflora. The tests include proximate and ultimate analyses, higher heating value, and thermogravimetric analyses; the potential of obtaining value-added products was also assessed through combustion in an advanced micro-gasifier stove. The testing procedure used to calculate performance characteristics of the stove was the world standard protocol WBT 4.2.3, and the results were analyzed in terms of thermal efficiency, specific fuel consumption and fuel burning rate. The measured variables including bed temperatures, exhaust gas composition and particulate matter were used to estimate the combustion characteristics of each fuel in terms of flame propagation, fuel burning rate and the combustion quality. The experimental outcomes provide important information on the impact of size and density of different fuels on flame propagation, fuel burning rate and indoor air quality. © 2018 Informa UK Limited, trading as Taylor & Francis Group.