Experimental profiles of stable species concentrations and temperature are reported for the flow reactor oxidation of ethanol at atmospheric pressure, initial temperatures near 1100 K and equivalence ratios of 0.61-1.24. Acetaldehyde, ethene, and methane appear in roughly equal concentrations as major intermediate species under these conditions. A detailed chemical mechanism is validated by comparison with the experimental species profiles. The importance of including all three isomeric forms of the C2H50 radical in such a mechanism is demonstrated. The primary source of ethene in ethanol oxidation is verified to be the decomposition of the C2H4OH radical. The agreement between the model and experiment at 1100 K is optimized when the branching ratio of the reactions of CzH50H with OH and H is defined by (30% C2H40H + 50% CHsCHOH + 20% CH3CH20) + XH. As in methanol oxidation, HOn chemistry is very important, while the H + 0 2 chain branching reaction plays only a minor role until late in fuel decay, even at temperatures above 1100 K.