Abstract : Top Lit-Up Draft (TLUD) gasification stove has a flame output at the top of the stove, the flame produced by this stove is held above the biomass at the point of mixing with secondary air. The stove design has an important role in improving its performance, there are also other components that are considered quite important, namely the addition of a chimney located at the top of the stove as a path for fire to escape. Although the design of the chimney plays an important role in the combustion that occurs in the TLUD gasification stove, there is still no systematic scientific study of the stove chimney design and its effect on the combustion of the TLUD stove. This study aims to determine the effect of chimney height on the performance of the Top-Lit Up Draft (TLUD) gasification stove. The chimney model with varying heights were 5 cm, 10 cm, and 15 cm, with an air flow velocity of 1.5 m/s. and biomass fuel: bagasse, as much as 600 grams. The dependent variables are fire height, flame temperature, flame duration, and stove thermal efficiency. This study concludes a.) the height of the chimney has an effect on the performance parameters of the resulting TLUD gasification stove, namely the flame height, flame temperature and flame duration [flame stability]. TLUD gasification stove performance parameters. b.) the height of the chimney has less effect on the value of the thermal efficiency of the TLUD gasification stove.