The study includes medicolegally examined fatal poisonings among drug addicts in 1997 in the five Nordic countries: Denmark, Finland, Iceland, Norway and Sweden, and the results are compared to a similar investigation from 1991. A common definition of "drug addict" was applied by the participating countries. The highest death rate by poisoning in drug addicts was observed in Denmark, where it was 6.54 per 10(5)inhabitants, followed by Norway with 6.35, Sweden with 2.21, Finland with 1.63 and Iceland with 1.20 per 10(5)inhabitants. All countries showed a higher death rate in 1997 than in 1991. For all countries the distribution of deaths according to geographical regions showed a decreasing number of drug deaths in the metropolitan area and an increasing number in other cities. Heroin/morphine dominated as the cause of death and was responsible for about 90% of the cases in Norway. In Sweden and Denmark, however, heroin/morphine caused only about 70% of the fatal poisonings. About 30% of the fatal poisonings in Denmark and Sweden were caused by other group I drugs, in Denmark mainly methadone and in Sweden mainly propoxyphene. Apart from two cases in Sweden methadone deaths were not seen in the other Nordic countries. In Finland heroin/morphine deaths have increased from about 10% in 1991 to about 40% in 1997. Forty-four percent of the fatal poisonings in Finland were caused by other group I drugs, mainly codeine and propoxyphene. The two fatal poisonings in Iceland were caused by carbon monoxide. Only few deaths in this investigation were caused by amphetamine and cocaine. A widespread use of alcohol, cannabis and benzodiazepines, especially diazepam, was seen in all the countries.