Experimental studies on molar distribution of CO/CO2 and CO/H-2 along the length of downdraft wood gasifier are reported in this paper. Sixteen numbers of special probes have been prepared and installed in various zones of the laboratory scale downdraft wood gasifier for generating data through exhaustive measurements of simultaneous concentration and temperature profiles along the length of gasifier using four different woody biomass materials in different shapes and sizes as a feedstock. Eight molar distribution for CO/CO2 and seven for CO/H-2 have been derived using these data of concentration and temperature profiles along the length of gasifier, while best molar distribution for both was decided based on comparison of their average absolute and bias errors and validated with present and published experimental data points of other biomass also. Both CO/CO2 and CO/H-2 distribution proposed in present work are found very close to measured values and thereby establish its acceptability. (C) 2009 Elsevier Ltd. All rights reserved.