Addition of oxygenates to diesel fuel has been found to reduce soot emissions, nonetheless, the resulting changes in the extinction and auto-ignition characteristics of the fuel mixture have not yet been fully understood. The present work investigates this aspect using laminar non-premixed flames. Dimethyl ether and methanol are two oxygenates considered in this study owing to their importance as potential alternative fuels/additives to gasoline and diesel. The fuel stream diluted with nitrogen is injected into a mixing layer from one duct of the counterflow burner, while air is injected from the other duct placed coaxially. The strain rate at extinction is calculated as a function of the mass fraction of fuel in the fuel stream. Further, the temperature of air at auto-ignition is determined as a function of strain rate for a fixed value of the mass fraction of fuel in the fuel stream. These data are obtained for the neat diesel, as well as for the blends of diesel and oxygenates. A flux analysis is used to explain the differences in extinction characteristics upon addition of oxygenates to diesel. A surrogate mixture of n-dodecane and m-xylene is used to represent the diesel fuel. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.