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The large size and complexity of many proteins constrains the reversed-phase high-performance liquid chromatography packings that are useful for their separation. Wide-pore, superficially porous, silica-based packings with solid 4.5-microm cores and a 0.25-microm porous outer layer (Poroshell) demonstrate a variety of characteristics that are beneficial for the separation of proteins. A shorter diffusion distance allows separations of large molecules at high linear velocities. This benefit over totally porous particles is clearly shown using separations of a peptide-protein standard. The structure and reduced surface area (4.5 m2/g) of these superficially porous particles simplifies interactions with its surface, resulting in improved peak shapes and resolution. Specialized bonding chemistries for low- and high-pH operation may be used to change band-spacing and achieve atypical separations. These rapid analysis options are demonstrated using protein standards and very high molecular weight glycosylated proteins including intact monoclonal antibodies, IgM, alpha2-macroglobulin, and glycophorin. In liquid chromatography-mass spectrometry analysis of a myoglobin peptide digest, bidentate-C18-bonded superficially porous packings achieve complete runs in 4 min and demonstrate an elution pattern that is unique from that of material bonded with sterically protected C18 ligands.