The packing of particles is important in the processing of the powders and in the ultimate properties of articles processed from the powders. Using an apparatus originally designed for the experimental determination of the packing density of powders, segregation effects with spherical and nonspherical particles with low aspect ratios were studied. The segregation of the powder samples according to particle sizes occurred upon vibration of the bed, following the well-known mechanisms of segregation according to size and elutriation segregation due to entrainment of particles in air. Segregation effects were also demonstrated with a melamine powder which consisted of nonspherical particles with low aspect ratios. Furthermore, additional data are provided for the packing density values of spherical particles with multimodal particle size distributions, which further support the theory of Ouchiyama and Tanaka on the packing of spherical particles, when segregation effects are not significant.