While longitudinal studies of delinquents and their behavior are extremely helpful, a review of the literature shows that the term chronic delinquent is poorly defined. A longitudinal study of 863 youths first referred to juvenile court in 1980 in Las Vegas, Nevada revealed two distinct categories of chronic offenders: chronic serious offenders and chronic nuisance offenders. Chronic serious offenders comprised 7.5 percent of the total and included those charged with felonies such as robbery and burglary. Chronic nuisance offenders comprised 9.4 percent of the total and included those who were not seriously criminal or disturbed. Instead, they committed status offenses; were petty thieves; or were runaways, truants, or loiterers. Chronic serious offenders were more likely to be school drop-outs, non-white, and male, and their first referral to the juvenile justice system was for a serious property crime. The article concludes by recommending that researchers avoid grouping chronic serious and chronic nuisance offenders and look at the differences in the nature of each group's first referral charge. 11 footnotes.