A simple, effective method for preparing an immunoadsorbent specific for anti-DNP antibody is described. The immunoadsorbent was made with a highly cross-linked polyacrylamide gel containing dinitrophenylated bovine serum albumin (DNP30BSA) as the antigen. The immunoadsorbent permitted the adsorption and subsequent elution of a mouse myeloma IgA (MOPC-315) with anti-DNP activity. The Fc and F(ab) fragments from MOPC-315 could also be separated effectively on this column. In addition, a non-precipitating mouse IgG anti-DNP-hemocyanin antibody was also isolated using the same immunoadsorbent.