We report on an experimental investigation of oxy-fuel combustion carried out in a co-axial, horizontally-fired swirl-stabilized burner. Retrofitting possibilities and flame extinction have been investigated with methane or liquefied petroleum gas (LPG) as fuel and mixtures of oxygen (O-2)-carbondioxide (CO2) or air as oxidant. Temperature profile measurements show that a higher oxygen concentration of around 33-34% by volume in the oxidizer is needed in oxy-fuel combustion to get temperature profiles similar to those for normal air combustion. Oxy-fuel flames have been found to be stable even for O2 concentrations less than 30% by volume, though at reduced peak flame temperatures. The results of extinction studies with CO2 or nitrogen (N-2) dilution indicate that CO2-diluted flames are more prone to extinction by dilution than N-2-diluted flames. The former get extinguished at an oxygen concentration of 21% by volume whereas the latter can be sustained at oxygen concentrations down to 15% by volume. (C) 2011 Elsevier Ltd. All rights reserved.