The growth of the worldwide collection of computer networks known as the Internet has led to a rapid increase in the quantity and variety of information available to scientists in mass spectrometry. It is now possible to learn about the latest mass spectrometric techniques, compare the capabilities of commercial instruments and participate in discussion with colleagues from around the world without ever leaving one's desk. The challenge that comes with the Internet information explosion is to learn how to navigate the various areas of the Internet and fully utilize these new information sources. It is also important to know how and where to ΓΌnd the most reliable information on a medium where quality cannot always be assured. The purpose of this paper is to provide a listing and brief discussion of on-line resources available for mass spectrometry. World Wide Web sites are tabulated for search pages, index pages for mass spectrometry research groups and companies, mass spectrometry societies, local discussion groups, journals and software. Usenet newsgroups and electronic mailing lists of interest to mass spectrometrists are listed and discussed.