Objective: To determine the association between mortality from violent or firearm related injury and previous handgun purchase. Methods: Case-control study of 213 466 Californians ages 21 and older who died in 1998; cases were the 4728 violent or firearm related injury deaths, with subsets by specific cause and means of death, and controls were the 208 738 non-injury deaths. The exposure of interest was the purchase of a handgun during 1996-98. The main outcome measure was the odds ratio for handgun purchase, adjusted for age, sex, race, education, and marital status. Results: Handgun purchase was more common among persons dying from suicide (odds ratio (OR) 6.8; 95% confidence interval (CI) 5.7 to 8.1) or homicide (OR 2.4, 95% CI 1.6 to 3.7), and particularly among those dying from gun suicide (OR 12.5; 95% CI 10.4 to 15.0) or gun homicide (OR 3.3; 95% CI 2.1 to 5.3), than among controls. No such differences were seen for non-gun suicide or homicide. Among women, those dying from gun suicide were much more likely than controls to have purchased a handgun (OR 109.8; 95% CI 61.6 to 195.7). Handgun purchasers accounted for less than 1% of the study population but 2.4% of gun homicides, 14.2% of gun suicides, and 16.7% of unintentional gun deaths. Gun suicide made up 18.9% of deaths among purchasers but only 0.6% of deaths among non-purchasers. Conclusion: Among adults who died in California in 1998, those dying from violence were more likely than those dying from non-injury causes to have purchased a handgun.A lthough firearm mortality rates in the United States have decreased since 1993, firearms accounted for 28 663 deaths in 2000 and ranked 11th among all causes of death.1 Gun homicide rates have fallen dramatically in the last decade, 2 but gun suicide rates have seen little change. In 2000 there were 16 586 gun suicides among persons age 21 and older, outnumbering the 10 801 gun homicides by 54%. Case-control studies find that gun availability increases risk of homicide, 3-6 while one cohort study finds this to be true for women, but not for men.7 With one exception, 8 studies of suicide have consistently shown that the risk of suicide increases when a firearm is available.3 5-7 9 The majority of these studies, however, inferred a passive exposure to a handgun (for example, a handgun present in the home). Little is known about the relationship between handgun purchase itself-the conscious decision to undergo a sustained close exposure to firearms-and subsequent risk of violent or firearm related mortality.In a cohort study of handgun purchasers in California in 1991, the purchase of a handgun was associated with a substantial increase in risk of firearm suicide that was present within a week of purchase and persisted for at least six years. 7 The continuing decline in overall rates of firearm related death since that study was conducted may have affected the association between handgun purchase and mortality. In addition, that earlier study left several important questions unanswered: Among those who die from...