Seventy-two of the 134 identified cases were registered in methadone maintenance treatment at the time of death. Diverted sources of methadone were implicated in the remaining 62 cases not registered in methadone maintenance treatment. Sixty percent of the individuals were single, 80 percent were unemployed, and 75 percent were males; their average age was 31 years. Intravenous injection of methadone prior to death was evident in 35 percent of the cases not in treatment and in 10 percent of those in treatment. Results revealed polydrug use in 89 percent of the cases; the most commonly used additional drugs included benzodiazepines, morphine, and alcohol. However, forensic authorities did not implicate other drugs in the cause of death in 34 percent of the cases. Findings suggested that the large proportion of deaths involving diverted sources of methadone may indicate high-risk behavior among some injecting drug users, who abuse methadone in combination with other drugs to enhance the effects of intoxication. Alternatively, heroin users who use illicit methadone may be doing so to medicate opioid withdrawal symptoms, which could suggest a high unmet demand for methadone maintenance treatment. Findings also suggested that the failure to implicate other drugs detected at autopsy in the cause of death may result in the over-reporting of methadone-detected cases as methadone-caused deaths. Findings support the need for an urgent review of the current classification and reporting mechanisms for methadone-related deaths. Tables, figures, and 13 references (Author abstract modified)