The effects of different parameters on performance and emissions of three biomass-fired stoves have been investigated. The parameters considered were moisture content of fuel, size of fuel, size of pot and method of ignition, while the selected stoves were an improved Indian stove, a Vietnamese traditional stove and an improved stove developed by the Royal Thai Forestry Department. It was found that increase in fuel moisture content resulted in decrease in stove efficiency, increase in the emission factor of CO and decrease in the emission factor of NOx; a slight decrease in CO2 emission factor was also observed, while emission of CH4 was not significantly effected. The fuel size did not show any significant influence on the efficiency of the stove, however, it showed significant influence on the emission of CO for the size range investigated. The size of pan did not affect the efficiency of the stoves tested. Two methods of stove ignition-conventional bottom ignition and top ignition-were investigated. In general, emission of CO and NO, was significantly less in case of top ignition in comparison with conventional bottom ignition.