As previously reported [Cameron, T. P., Rogers-Back, A. M., Lawlor, T. E., Harbell, J. W., Seifried, H. E., and Dunkel, V. C. (1991) Gentoxicity of multifunctional acrylates in the Salmonella/mammalian-microsome assay and mouse lymphoma TK+/- assay. Environ. Mol. Mutagen. 17, 264-271], the National Cancer Institute (NCI) shares the responsibility of selecting the most significant chemicals for carcinogenicity testing by the National Toxicology Program (NTP) and has used data from Salmonella and mouse lymphoma mutagenicity assays to aid in the selection and prioritization of chemicals to be further evaluated in chronic 2 year rodent studies. In addition, a number of antineoplastic and anti-AIDS drugs in preclinical evaluation were tested for the NCI's Division of Cancer Treatment Toxicology Branch. In the NCI/NTP chemical selection process, it is no longer necessary to test chemicals prior to sending them to the NTP so the NCI program has ceased performing mutagenicity tests. Some of the testing data has been made available in summary form in the Chemical Carcinogenisis Research Information System (CCRIS), which is searchable on the NLM TOXNET system. The limitations in using this source are that only summary results are available and many negative test results are not included. A summary table that presents the results for each compound is provided in the Appendix with raw data provided in the Supporting Information. The Appendix table contains the compound name, CAS number, and a summary of the data from the Ames test and the mouse lymphoma assay.