The effect of microwave heating on diesel soot combustion was studied through the use of a microwave heated thermogravimetric analyzer (TGA). A TGA was designed around a commercial multimode microwave oven so that carbon weight loss resulting from microwave heating could be measured. The oven door was modified, allowing infrared thermography to be used to measure soot combustion temperatures. Measurements suggest that the actual temperature of the oxidizing carbon (which is in the interior of the powder bed) is hotter than the surface temperature one measures by IR thermography. Thus, the apparent reduction in soot combustion temperature with microwave heating reported in some literature may be the result of the inability to measure the interior temperature of the soot/catalyst mass. (C) 2005 Elsevier B.V. All rights reserved.