In the majority of episodes of fatal interpersonal violence, the weapon used is a firearm. Amid frequent reports of youths carrying weapons, including firearms, we conducted a case-control study to identify risk factors for being charged with gun-carrying and gun-carrying, per se, among adolescents in Jefferson Parish, Louisiana. Cases were defined as incidents of gun-carrying among adolescents < 19 years of age, legally charged in the Jefferson Parish, Louisiana, juvenile court from January 1, 1992, through April 15, 1993. For each case, we randomly drew three age-, gender-, and school-matched control subjects from the enrollment rosters of the Jefferson Parish public schools and administered a questionnaire. The data set comprised 38 case subjects and 103 matched control subjects. Thirty (29%) control subjects reported gun-carrying. Both case subjects and gun-carrying control subjects reported self-defense (40%) as the main reason for gun-carrying. Most case subjects (25 [66%]) were African Americans, but only 8 (27%) gun-carrying and 27 (37%) non-gun-carrying control subjects were African Americans. Case subjects were significantly more likely than gun-carrying control subjects to report being African American (odds ratio [OR] = 5.3, 95% confidence intervals [CI] = 1.6, 17.5). In crude analyses, case subjects were more likely than non-gun-carrying control subjects to report adult-male unemployment among households with adult men, to foresee a likelihood to be shot in school, to have seen a shooting, to use marijuana, to watch television > 6 hours per day, and to be African American. After the effect estimates were adjusted in conditional logistic regression modeling, case subjects were more likely than non-gun-carrying control subjects to report adult-male unemployment among households with adult men, using marijuana, and watching television > 6 hours per day (OR = 8.6, 95% CI = 1.2, 61,2; OR = 11.7, 95% CI = 2, 70.2; and OR = 6.5, 95% CI = 0.8, 51.9, respectively). Gun-carrying control subjects were significantly more likely than non-gun-carrying control subjects to report their school not safe, having seen a shooting, using marijuana, and having fired a gun (OR = 9, 95% CI = 1, 82.1; OR = 7, 95% CI = 1.3, 38.2; OR = 6.8, 95% CI = 1.8, 25.5; and OR = 17, 95% CI = 1.8, 156.6, respectively). We found that gun-carrying was very common, and that adolescent youths who carry guns were more likely to have familiarity with guns and experience with or perception of an unsafe environment. Together, these lead to the conclusion that gun-carrying is a common response of youths who live in a risky environment, who do not have the social support to learn how to deal effectively with that risk, and who have access to guns, which they think may provide them with some protection.