Many existing data systems or registers can be used to study occupational exposures and reproduction. Use of these data systems, especially those already computerized, results in great savings in time and resources. The report describes existing record systems on reproductive outcomes and/or occupational exposures and approaches to linking data, using examples drawn primarily from the United States and the Nordic countries. Some existing systems are more useful than others for research. A perfect record system would include data collected in a standardized manner, have complete coverage of the universe of events, and be error-free as a result of editing and verification for completeness and accuracy. Such a system would also include unique personal identifiers to permit linkage of these data with other systems. (Copyright (c) Occupational Medicine: State of the Art Reviews, 1(3), July-Sept. 1986.)