For agents classified by IARC as known or suspected human carcinogens and for over 100 other chemical pesticides, solvents, intermediates and final products, we have extracted and recorded qualitative and quantitative genetic bioassay data available in the literature. Either the lowest effective dose (LED) or the highest ineffective dose (HID) tested was recorded for each agent and bioassay system. The systems were organized according to classes of genetic activity and subdivided by the phylogenetic level of the test organism. For each compound, the quantitative results in the test systems were represented by computer-generated bar graphs, so-called 'genetic activity spectra.' Statistical methods and pattern recognition techniques were used to evaluate the activity profiles of compounds in a pairwise manner. The results showed that structurally similar compounds frequently displayed qualitatively and quantitatively similar profiles of genetic activity. As the database is enlarged, the analysis of genetic activity profiles may contribute to our understanding of structure-activity relationships and mechanisms of action of chemical agents. Such a method of presentation could well serve as a medium for international exchange and evaluation of genetic bioassay data.