The focus was on access to, carrying of, and the intentional use of handguns by youth in late adolescence (high school age). The primary concern was the mortality associated with violence, including homicide and suicide. It was found that national homicide rates involving youth between 15 and 18 years of age escalated in the mid-1980's through the early 1990's and then began to decline. Colorado experienced a similar trend, although the time of onset was the late 1980's. For both the Nation and Colorado, males using handguns as lethal weapons drove the trends. While national and Colorado trends were similar, recent youth homicide rates in Colorado were about half the magnitude of national rates. Between 1989 and 1995, 50 to 75 percent of suicides involved the use of some type of firearm by youth between 15 and 19 years of age. Like homicide, firearm suicide rates were significantly higher for males than females, both nationally and in Colorado. The rate for males in Colorado, however, was about 50 percent higher than the national rate. Implications of the findings for preventing youth handgun violence are considered. Various gun violence prevention programs are described that include community crisis intervention and counseling programs, hospital-based injury prevention programs, community-based youth outreach, public awareness campaigns, legal justice system intervention programs, neighborhood prevention and intervention programs, family-based gun injury prevention, school-based prevention and intervention efforts, and peer group prevention and intervention efforts. Suicide prevention strategies are also examined. Additional information is appended on gun violence prevention programs, suicide prevention programs, and youth handgun violence. 59 references, 13 tables, and 17 figures