Residue analysis of the pyrethrins and allethrin as well as newer pyrethroid insecticides not containing halogens such as resmethrin and phenothrin is expensive, tedious, and/or of poor sensitivity. The structure of such pyrethroids suggests that they can be analyzed quickly, inexpensively, and at low levels by radioimmunoassay. Reaction of S-bioallethrin (lR,3R,4'S) with carboxymethoxylamine hemihydrochloride led to quantitative conversion to its carbomethoxyoxime derivative. Alternatively, hydroboration-oxidation of S-bioallethrin with disiamylborane led to selective oxidation at the terminal olefin with little loss of specific rotation. Quantitative reaction with succinic anhydride gave S-bioallethrin hemisuccinate which was conjugated via its N-hydroxysuccinimide active ester to tyramine, hemocyanin, or bovine serum albumin (BSA). Rabbits immunized with allethrin-hemocyanin yielded a serum reacting with hemocyanin or allethrin-BSA but not BSA as determined by immunodiffusion. Appearance of the precipitin band to allethrin-BSA could be inhibited by S-bioallethrin, but not by higher levels of permethrin, parathion, carbaryl, DDT, or an inactive allethrin isomer (lS,3R,4'R). The potential of immunochemical methods for residue analysis is discussed.