Human secretory component bound covalently to Sepharose 4B has been used as an affinity adsorbent to isolate and purify polymeric immunoglobulin from cell culture supernatants. The method was used to isolate murine IgM isotype anti-trinitrophenol antibody and rat IgM isotype anti-lymphocyte antibody from hybridoma cell culture supernatants. Gel filtration of the eluted antibodies followed by enzyme immunoassay showed that all recovered IgM was of pentameric molecular size. Murine IgA isotype anti-dinitrophenol antibody and murine IgA anti-human rotavirus antibody were isolated from cell culture supernatants of a plasmacytoma and a hybridoma respectively. Most of the IgA recovered following affinity adsorption with secretory component was of greater molecular size than dimer. Murine IgG was not adsorbed by secretory component bound to Sepharose. Eluted antibody retained antigen binding activity. Affinity chromatography using human secretory component bound covalently to a solid phase provides an antigen-independent technique for purification of murine and rat IgA and IgM polymeric immunoglobulin from cell cultures.