Combination chemotherapy remains the major current treatment of non-Hodgkin s lymphoma. B-cell lymphoma often has tumor-specific surface immunoglobulins called idiotypes. Clinical trials using murine monoclonal anti-idiotype antibodies as a targeting approach have shown some success. I describe a novel concept of using idiotype-specific peptides as an alternative targeting approach for the treatment of B-cell lymphoma. In brief, octapeptides that bind to the surface idiotype of the B-cell lymphoma are isolated from a large synthetic peptide library (10(6) to 10(7) peptides). Once the sequence of a tumor-specific octapeptide ligand is defined, large quantities can be synthesized and conjugated with a radionuclide (such as iodine 131). This should permit highly specific destruction of lymphoma cells that bind the labeled peptide. The theoretic advantages of this approach over the previous use of anti-idiotype antibodies are addressed.