The heat fluxes from premixed Ox methane flames (temperature around 2800-3000 K) of various equivalence ratios have been measured and the values compared with those predicted on the basis of the following models:- (1) Re- combination reactions of dissociated species are frozen in the boundary layer and the surface is noncatalytic. (2) Equilibrium is maintained throughout the boundary layer, but the Lewis number of all atoms and radicals is unity. (3) Heat transfer by diffusion and recombination of hydrogen atoms is more rapid than heat transfer by ordinary conduction, that is, there is a Lewis number augmentation effect. The comparison, for the regions of the flames away from the reaction zone, have shown that the model No. 1 leads to serious underestimations and that the experimental values fall between those calculated on the basis of mechanisms "2" and "3". In the vicinity of the reaction zone, all the three mechanisms underestimated the predicted values.