The development of the Industrial Hygiene Information System (IHIS) was described. The IHIS has been a collaborative effort between the NIOSH and the National Cancer Institute (NCI) using data from records of exposure assessments conducted by the Industrial Hygiene Section of the Industrywide Studies Branch, NIOSH. The goal of the IHIS has been to provide a resource for exposure assessment in epidemiologic studies. The IHIS was designed to accommodate NIOSH and NCI workers trying to identify new work groups to study, investigators building a job exposure matrix to support a study, and those performing health risk assessments. The information included on the IHIS from each report was basic data about the survey, general facility information, process and operation activities, control methods, and NIOSH and nonNIOSH personal exposure and area concentration summary and detail data. Methods for searching the IHIS, types of data contained in IHIS outputs, software used, database management, quality assurance, access, and future plans were described.