Different methods of sample preparation for determination of di- and polyamines (putrescine, spermidine, spermine) and their conjugates in serum, plasma, and urine are discussed. Higher polyamine values obtained after hydrolysis of serum or plasma acidic extracts suggest the presence of polyamine conjugates. Additional polyamines might be bound to proteins and released by hydrolysis of the crude samples. Biological studies of bound polyamines in health and disease will require procedures for quantitative analysis. For the pertinent measurements, radioimmunoassays employing antibodies developed against isolated polyamine conjugates may prove useful.