Structure activity relationships have been adapted to aid in selecting compounds for large-scale screening in mouse lymphocytic leukemia (P388). Molecular fragment statistcs from compounds tested in P388 are used to estimate antitumor activity, novelty and toxicity. These estimates are examined by a medicinal chemist along with the structures of over 30,000 potential acquisitions per year to decide which compounds to screen. Results from P388 on almost 20,000 compounds that have been through this system indicate that the estimates are useful. New estimates are planned for therapeutic index and activity with regard to physical parameters. In addition, these methods have yielded an automated literature surveillance project.