Injuries are a significant public health problem and among the leading causes of death worldwide. In Finland, nearly 1.2 million accidents or assaults lead to physical injury annually. This study examined the nationwide trends in unintentional injury deaths of adults in Finland. For this purpose, we obtained from the Finnish Official Cause-of-Death Statistics (OCDS) the data for persons aged 15 years or older whose deaths occurred in 1971–2008 due to an unintentional injury. A drastic decline occurred in road traffic crashes. The age-standardized death rate (per 100 000 person-years) of men's road traffic crashes was 48 in 1971 but only 10 in 2008. Traffic caused fewer deaths in women than men, but the declining trend in women's death rates was also clear, from 17 in 1971 to 3 in 2008. During the study period, falls became the leading category of men's unintentional injury death, although their rate rose rather slowly from 19 in 1971 to 21 in 2008. Among Finnish women, the rate of fall-induced deaths declined from 32 in 1971 to 16 in 2008. There was a notable rise in men's unintentional alcohol poisoning deaths, especially since 2003. In 2008, alcohol poisonings were the second leading cause of men's injury death (rate 18). The rate of women's deaths due to alcohol poisoning was yet low during the entire study period but its rise was clear, from 1 in 1971 to 5 in 2008. Poisoning deaths caused by other substances also increased: among men their rate was 4 in 1971 and 11 in 2008, and among women 2 in 1971 to 4 in 2008. Between 1998 and 2008, psychotropic drugs, narcotics and opioid analgesics caused the majority of both men's and women's non-alcohol poisoning deaths. In conclusion, unintentional injury deaths in road traffic crashes declined steeply among adult Finns during 1971–2008. The rate of fall-induced deaths in Finnish men was rather stable during the study period while in women it clearly declined. In contrast, increase in poisoning deaths due to alcohol and other substances was alarming. Vigorous preventive actions should be initiated to control this development.