The report focuses on the quantitative profiles of genetic activity produced by 65 pesticides and efforts to classify them according to their genotoxic effects and chemical structures. Three main categories may be distinguished based on the qualitative results: Category 1 pesticides were active in most of the in vitro and in vivo assays employed. These nine compounds include the structurally similar organophosphate insecticides, acephate, demeton, monocrotophos, and trichlorfon; the phthalimid fungicide analogues, captan and folpet; and the thiocarbamate herbicide analogues, dialiate, sulfallate and triallate. The 26 Category 2 compounds demonstrated fewer positive results and may be subdivided into two parts, one of which contains 12 halogenated aromatic or heterocyclic ring compounds, including the phenoxy herbicides, 2,4-D, 2,4-DB, and 2,4,5-T. The remaining part of Category 2 (14 compounds) consists of structurally similar organophosphate insecticides, azinphos-methyl, crotoxyphos, disulfoton, methyl parathion; three similar ethylenebisdithiocarbamate fungicides, maneb, mancozeb, and zineb; three similar pyrethroid insecticides, allethrin, chrysanthemic acid, and ethy chrysanthemate; and four structurally diverse compounds, cacodylic acid, dinoseb, sec-butylamine and benomyl. The third category of 30 pesticides gave negative results in all tests and represents structurally diverse compounds. Using the computerized profile matching methodology, from 2080 possible pairwise chemical combinations of the 65 pesticides, 20 statistically significant pairs were selected. (Copyright (c) 1986 Elsevier Science Publication B.V.)