Experimental results of the fuel-lean, stoichiometric, and fuel-rich oxidation of methanol and ethanol using two fused silica tubular flow reactor systems are reported. For the initial set of experiments, semi-quantitative reaction byproduct data were obtained using in-line GC-MS analysis. Subsequent quantitative experiments with a second flow reactor system were conducted with an in-line water trap coupled to GC-TCD analysis. A much larger number of reaction byproducts were observed for ethanol than methanol. For methanol, observed reaction byproducts were acetone, formaldehyde, 1,2,3-trioxane, methane, ethane, and ethene. For ethanol, observed reaction byproducts were acetone, acetaldehyde, formaldehyde, acetic acid, methane, ethane, ethene, ethyne, and propene. Favorable comparisons of the flow reactor data with vehicle emission test results are presented.