Four open core throatless batch fed rice husk gasifier reactors having internal diameters of 15.2, 20.3, 24.4 and 34.3 cm were designed and fabricated. Each reactor connected with gas cleaning unit was tested for its performance characteristics. On each reactor ten trial runs were conducted varying the air flow rate or specific gasification rate. Gas quality, gas production rate, gasification efficiency specific gasification rate, and equivalence ratio were determined for every run on each of the four reactors. It was found that for each reactor the gasifier performance was the best at a specific gasification rate of around 192.5 kg/h-m(2) Under the best operating conditions, the equivalence ratio was 0.40 and the gasification efficiency was around 65%. These parameters may be used for designing rice husk operated throatless gasifiers in the capacity range of 3-15 kW. (C) 2000 Elsevier Science Ltd. All rights reserved.