Using the most recent data from the FBI's Uniform Crime Reports, this study focused on arrest data. The number of arrests that involved juveniles in 1999, 2.5 million, was 9 percent lower than the number of arrests in 1995. Arrests for many of the most serious offenses declined substantially between 1995 and 1999. During this period, arrests for murder dropped 56 percent among juveniles; robbery arrests were 39 percent lower; burglary arrests fell 23 percent; and juvenile arrests for motor vehicle theft were down 35 percent. The small size of the total decline in juvenile arrests (9 percent) was largely due to the influence of increasing arrests for some of the less serious offenses. Even controlling for changes in the juvenile population, the rate of decline in juvenile arrests between 1995 and 1999 outpaced that of other age groups. The contribution of juveniles to the total decrease in violent-crime arrests can be estimated by calculating the decrease in the number of arrests involving juveniles and comparing it to the decrease for offenders of all ages. The results of this comparison suggest that juveniles accounted for a decrease of 43,800 arrests, which was 29 percent of the overall decrease in violent-crime arrests between 1995 and 1999. Older youth, on the other hand, accounted for 23 percent of the decline, and adults ages 25 and older accounted for 49 percent of the total decrease. Juveniles and older youth combined contributed to 38 percent of the increase in violent-crime arrests between 1985 and 1995, but they accounted for 51 percent of the subsequent drop in violent crime between 1995 and 1999. 8 figures and 3 references