A phenomenological model of downdraft gasification under steady state operation is developed based on previously published values for the reaction kinetics in the reduction zone. The model predicts a product gas with a composition similar to that found experimentally, although the model over-predicts the methane concentration. The accuracy of the model is limited by the availability of data on the initial conditions at the top of the reduction zone. (C) 2003 Elsevier Science Ltd. All rights reserved.