During October 1973 through May 1998, 157 snowmobile fatalities were autopsied in Northern Sweden, including 131 riders, 15 passengers, six occupants with unknown position and five victims pulled by a snowmobile. Most fatalities occurred during March and April (41%), on weekends/holidays (75%), between 18:00 and 02:00 h (59%), during darkness (63%), in clear weather (84%) and at leisure time (94%). The median age was 39 years and 92% were men. The most common causes of death were blunt trauma (53%) and drowning (38%). A total of 64% were inebriated by alcohol, with a mean blood alcohol concentration of 1.7 g/l. More inebriated victims were found during weekends/holidays than on weekdays (75 vs. 51%) and during nighttime than during daytime (92 vs. 52). Driving into water was the most common event (38%) followed by collisions with immobile objects (20%). Alcohol and speeding were the most common contributors to the crashes, while flotation snowmobile suit and helmet use were considered to be the most important injury prevention factors.