With the objective of providing a data set for evaluation of models of turbulent diffusion flames, a co-axial, ducted, turbulent, diffusion flame was mapped in terms of static pressure, impact pressure, and chemical composition. From these data velocity components, densities, turbulent exchange coefficients, and reaction rates of O 2 , C 3 H 8 , CO, CO 2 , H 2 O, H 2 , CH 4 , and C 2 H x were computed. The overall fuel equivalence ratio of the flame was 0.615; the fuel and air entrance velocities were approximately equal at 13 m/s; and the overall heat release rate in the region studied was 50×10 6 j/(m 3 s). Soot formation was found to be negligible, and the mixing similarity principle of Browne and Powell was used in obtaining results. The maximum rate of oxygen consumption was found to be in regions of the flame where the equivalent unburned composition was either fuel rich or near stoichiometric. The rates of oxygen consumption are markedly less than for comparable premixed propane-air flames or hydrogen-air diffusion flames. It was found that the mol fraction of water and the sum of the mol fractions of CO and CO 2 were correlated with the mol fraction of oxygen. Only the principal results are summarized herein. The full data set is available elsewhere.