Significant advances have been made in analytical technology for the characterization and identification of particles present in pharmaceutical products.  With these advances comes a tremendous amount of new data with which to characterize biologics, devices, and small molecules.  In parallel with these technological advances, the regulatory agencies have shown increased interest in more in-depth characterization of therapeutic products.  Careful interpretation of data and deeper understanding of the method limitations is of utmost importance when using complementary methods to characterize particle profiles of therapeutic products for regulatory submissions. This presentation demonstrates how multiple particle techniques can be used to adequately characterize therapeutic products and their particle populations.