Particle shape of aluminum alloy powder is quantitatively characterized by means of stereological method, With two-dimensional digitized images the stereological parameters that qualify the shape, are determined through the use of computer programs. The results are statistically evaluated and described in graphics to determine their behavior in dependence of the particles size. In general the results agree with the principles of stereology; the Bulkiness Factor parameter is the most representative of the shape, while the Compactness Factor is very sensitive to the changes of particles size. Different parameters that determine a same peculiarity of the shape present similar behavior.