The number and type of fireworks injuries occurring around New Year's Eve as well as type of fireworks used was investigated with the aim of guiding future prophylactic efforts. All patient contacts to emergency rooms throughout Denmark that were due to fireworks were prospectively registered for twenty-four hours before and after New Year's Eve 1995/1996 and 1996/1997. The number of fireworks injuries increased by 13.9% from 381 to 433, and the number of serious injuries increased by 50.8%. In 1996/1997 50% of the injuries were hand injuries, 19% were eye injuries, 8% were injuries to the head and neck, and the remaining 23% were hearing injuries and miscellaneous injuries. Seventy percent of the serious injuries were hand injuries, leading to some form of amputation in a third of cases. Sixty-one percent of the admissions were due to illegal fireworks. It is concluded that the number of serious fireworks injuries is on the increase, and that the main part of these injuries are hand injuries. Over half of the the serious injuries were due to illegal fireworks. Prophylactic efforts should be aimed against hand-held and illegal fireworks.