Abstract: Gossypol (8, 8'-dicarboxyaldehyde-1,1', 6,6', 7,7'-hexahydroxy-5,5'-diisopropyl-3,3'-dimethyl-2,2'-binaphthalene) is a constitutent of cotten seed. As part of a study of the properties of gossypol, a sample of radioactive material is needed for in vitro experiments. Tritiated gossypol is obtained by catalyzed isotopic exchange in ethyl acetate solution with tritium gas in the presence of PdO/BaSO4. The specific activity of the tritiated material purified by silicon gel-loaded paper chromatography is 2.2 Ci/mM with radiochemical purity over 95%.