In 2003, an estimated 31,484 suicides (10.7 per 100,000 population) occurred in the United States. Suicide was the fourth leading cause of death among persons aged 10-64 years and the second and third leading causes of death among persons aged 25-34 and 10-24 years, respectively. Few studies have attempted to determine the contribution of substance use to suicide. To assess toxicology testing practices and to determine the prevalence of positive results for alcohol or other drugs, CDC analyzed test results of suicide victims in the 13 states that collected data for the National Violent Death Reporting System (NVDRS) in 2004. This report summarizes the results of that analysis, which determined that 1) the percentage of suicide victims tested varied among states, ranging from 25.9% to 97.7%; 2) of those victims tested, 33.3% were positive for alcohol, and 16.4% were positive for opiates; and 3) similar percentages of poisoning suicide (i.e., suspected intentional overdose) and nonpoisoning suicide victims tested positive for alcohol or other drugs, with the exception of opiates. These results underscore the need to continue monitoring toxicology test results of suicide victims, which might identify patterns of substance use that can help guide development of effective suicide interventions. Such data can be enhanced by uniform, comprehensive, toxicology testing practices on a state and national basis.