In 1990, 19,722 persons between 1 and 34 years of age died as a result of firearm injuries, a figure representing 17.6 percent of all deaths for that age range. Among children between 10 and 14 years of age, 560 died from firearm injuries, accounting for one of every eight deaths. Among teenagers between 15-19 years and young adults between 20-24 years, one of every four deaths was caused by firearm injuries. For adults between 25 and 34 years of age, one of six deaths was due to firearms. Within these age groups, variations by race and sex were large. The majority of homicides among teenagers and young adults between 15-34 years resulted from the use of firearms. The age-specific proportion of suicides due to firearms was lower than the proportion of homicides. Consistent with earlier patterns, virtually no change occurred from 1985 to 1990 in the overall firearm death rate among young children between 1 and 9 years of age. For children aged 10 to 14 years, however, the firearm death rate increased by 18 percent over the period. The total firearm death rate among teenagers between 15 and 19 years of age increased by 77 percent from 1985 to 1990, to 23.5 deaths per 100,000. The firearm death rate among persons 20 to 24 years of age was 36 percent higher in 1990 than in 1985. By ages 25-34, the upward trend in age-specific firearm mortality slowed considerably. Sixty percent of all deaths among persons between 1 and 34 years of age resulted from intentional and unintentional injuries in 1990, and about 30 percent of those external deaths were from firearms. 7 references, 6 tables, and 6 figures