The size, shape and surface topology have a strong influence on powders properties, such as: mechanical, optical, catalytic, etc. In addition, when particles have a nanometer size, the dispersion of these features plays an important role. There are a number of techniques, which could be used in order to characterize powders in terms of particle size and shape. However, due to the scale of analysis, well beyond the wavelength of visible light, most of them cannot be applied for investigations of nanopowders. In this paper, transmission electron microscopy (TEM) image analysis and X-ray methods are presented as promising and complementary techniques. An example of their application to ZrO2, nanopowder is shown. The advantages and limitations of each method are described. (c) 2006 Elsevier B.V. All rights reserved.