Drug overdose death rates have increased steadily in the United States since 1979. In 2008, a total of 36,450 drug overdose deaths (i.e., unintentional, intentional [suicide or homicide], or undetermined intent) were reported, with prescription opioid analgesics (e.g., oxycodone, hydrocodone, and methadone), cocaine, and heroin the drugs most commonly involved.1 Since the mid-1990s, community-based programs have offered opioid overdose prevention services to persons who use drugs, their families and friends, and service providers. Since 1996, an increasing number of these programs have provided the opioid antagonist naloxone hydrochloride, the treatment of choice to reverse the potentially fatal respiratory depression caused by overdose of heroin and other opioids.2 Naloxone has no effect on non-opioid overdoses (e.g., cocaine, benzodiazepines, or alcohol).3 In October 2010, the Harm Reduction Coalition, a national advocacy and capacity-building organization, surveyed 50 programs known to distribute naloxone in the United States, to collect data on local program locations, naloxone distribution, and overdose reversals. This report summarizes the findings for the 48 programs that completed the survey and the 188 local programs represented by the responses. Since the first opioid overdose prevention program began distributing naloxone in 1996, the respondent programs reported training and distributing naloxone to 53,032 persons and receiving reports of 10,171 overdose reversals. Providing opioid overdose education and naloxone to persons who use drugs and to persons who might be present at an opioid overdose can help reduce opioid overdose mortality, a rapidly growing public health concern.