The experience gained at the Industrywide Studies Branch of NIOSH has resulted in the identification of the following three principles which, if adopted, could enhance the quality of epidemiological research studies being conducted. The first principle called for an open scientific review of protocols and final reports. Such a review will improve the research design, result in a better understanding of the study by all involved persons, and enhance the credibility of the research. The second principle called for the dissemination of the information gained in the study to all appropriate parties including the scientific community, the nonscientific community in industry and labor, and the subjects of the studies. Knowing that such dissemination will occur can improve the attention given by researchers to the interpretation of the study. The third principle was to incorporate new scientific methods into research studies and to use expertise from other disciplines when appropriate. Academic, government, and industry epidemiologists have been limited by the quality and quantity of the exposure data collected and maintained by industry. Some of these companies have developed programs involving the routine industrial hygiene monitoring that accurately characterizes the exposure of workers and adequate record keeping that permits linkage of industrial hygiene data with epidemiologic data such as work histories and health outcomes. Experts in additional disciplines should be used to assist in designing the study, conducting the research and interpreting the results.