Although developed societies have undergone many profound changes during recent decades, including urbanization, increased traffic and aging of the populations, epidemiologic information on secular trends in profiles of injuries is limited. We investigated such trends in Finland by selecting from the National Hospital Discharge Register all Finns aged 15 years or more who required hospital treatment because of an unintentional injury during 1971-1995. The injury incidences were expressed as the number of patients per 100,000 individuals per year. In Finnish men, road traffic accidents and falls, the two leading causes of injury, produced equal numbers of injuries in 1971 (4935 and 4957), but thereafter the role of the traffic accidents gradually decreased (3512 injuries with unadjusted and age-adjusted incidences of 177 and 183 in 1995) and that of falls clearly increased (13,218 injuries with unadjusted and age-adjusted incidences of 664 and 635 in 1995). Changes in the other injury categories of men were less drastic. In Finnish women, falling was the most common cause of injury in 1971 (5051 injuries), after which its role increased sharply, to 17,250 injuries in 1995 (unadjusted and age-adjusted incidences of 804 and 698, respectively). In 1971, road traffic produced 2369 injuries in women, after which this number somewhat decreased (2160 injuries with unadjusted and age-adjusted incidences of 101 and 101 in 1995). The role of all the other injury categories was small in Finnish women during 1971-1995. We conclude that a quick change in the overall profile of injuries occurred in Finland in 1971-1995, a change in which falls replaced road traffic accidents as the major cause of a serious injury. This epidemiologic change will give a new challenge for injury prevention in the new millennium.