In order to facilitate the in situ localization of cyclic nucleotides, a large supply of high-titer anti-sera for immunohistologic analyses would be valuable. Therefore, monoclonal antibodies (Mab) directed at 2'-0-succinyl cyclic GMP (s-cGMP) or 2'-0-succinyl cyclic AMP (s-cAMP) were generated. Immunized mice developed polyclonal antibodies of high titer to either cyclic nucleotide as reflected in an enzyme-linked immunosorbent assay (ELISA) employed to monitor these anti-sera. With the use of standard hybridoma technology and ELISA to monitor anti-cyclic nucleotide antibody production from positive clones, several Mab-producing clones were grown to large volume in tissue culture and ascites fluid. The anti-cGMP and anti-cAMP anti-sera, which demonstrated significant ELISA titers at greater than 1:2,000,000 dilutions, are monospecific and can be employed for radioimmunoassays, ELISA, or immunohistologic localization of cyclic nucleotides in situ.