The National Electronic Injury Surveillance System (NEISS) includes data about nonfatal occupational injuries and illnesses treated in U.S. hospital emergency departments (EDs). This report summarizes 1998 injury and illness estimates based on NEISS, which indicate that the magnitude and patterns of nonfatal occupational injuries and illnesses were comparable to estimates reported for 1996. Younger workers continue to have the highest rates of work-related injuries and illnesses; therefore, interventions should address the health and safety needs of young workers, most of whom lack substantial experience in the work place. In 1998, NEISS identified approximately 47,000 work-related injuries and illnesses treated in 67 EDs derived from a national stratified probability sample of all U.S. hospitals with a minimum of six beds and a 24-hour ED. The NEISS sampling frame for work-related ED visits was updated in October 1997 based on the 1995 listing of U.S. hospitals with EDs. As a result, compared with earlier reports, the updated hospital sample had changes in the makeup of hospitals within each size stratum in the sample and the statistical weights for cases, which are used to extrapolate to national estimates.