Laboratory temperature programmed oxidation (TPO) is popular for diesel soot oxidation catalyst screening. The method of depositing soot on the catalyst can be critical for the measured catalyst performance. Different methods for bringing the soot in physical contact with the catalyst were evaluated in order to determine which methods give a realistic contact. Suitable methods are filtration from a (artificial) soot aerosol, shaking in a sample bottle, mixing with a spatula, and dipping in a soot dispersion. For these preparation methods Printer U synthetic soot is a suitable model compound. (C) 2000 Elsevier Science B.V. All rights reserved.