EPILEX is a disk-based multilingual lexicon of epidemiological terminology for use on a PC-compatible computer. Lexicographers in seven languages participated in its production, with the support of the European Commission. This tool is designed to be of aid to Europeans, Americans both North and South and others who use European languages. It provides complete versatility so that any two of the languages may be paired and either language selected to establish the alphabetical order. Useful pairings may also be printed in order to build personalized lexicons. The lexicon is based on John Last's "Dictionary of epidemiology" (Oxford University Press). Over 200 further words have been added as seen fit by the lexicographers.