Drug addicts who had died in Copenhagen City and County in 1981 and 1989 were analysed for methadone. In 1981, 94 cases were analysed of which 16% were found positive for methadone, and in 1989, 70 cases were analysed of which 37% were positive. Methadone alone was found to be the cause of death in 50% more cases in 1989 than in 1981. Only half of the drug addicts who were found positive for methadone had been under methadone treatment. Morphine and benzodiazepines were the most frequently occurring other substances in both 1981 and 1989. Alcohol was found in only about 30% of the methadone-positive cases. The median whole blood concentrations of methadone found in addicts where methadone was the cause of death was 0.3 mg/kg where no alcohol was present and 0.2 mg/kg where alcohol was present. In living persons using methadone, the median was 0.1 mg methadone/kg whole blood with or without alcohol present.