Abstract BACKGROUND: Alpine skiing and snowboarding have a substantial risk of injuries. Many studies describe injuries related to activities in alpine resorts, but few focus on the off-piste area. The knowledge is therefore limited. This study describes the injuries among skiers and snowboarders in the off-piste area in a major Norwegian alpine resort and aim to uncover trends in incidence and injury characteristics between 2001 and 2011. STUDY DESIGN: Longitudinal study. METHODS: All injuries in Hemsedal Skisenter, one major Norwegian alpine resort, have been recorded over the last 30 years. Data from 2001, 2004, 2007 and 2011 were used. The total number of injuries were (N=3397) This study focus on the off-piste cases (N=400). Injury type, injury cause, injured part of the body, skill level, equipment and helmet use were recorded. A computer analysis (NCSS 9) was used to uncover significant changes between 2001 and 2011, and differences between injuries from the off-piste group and the control group. RESULTS: The number of visitors in Hemsedal Skisenter has increased from 443 965 in 2001 to 507 703 in 2011. Injuries off-piste in Hemsedal Skisenter: A significant reduction in the proportion of off-piste injuries in Hemsedal Skisenter was observed from 2001 (15.6 % of total injuries) to 2011 (10.1 % of total injuries) (p<0.01). In 2011, 65.1 % of the injured people were alpine skiers. Among the injured people 82.5 % classified themselves as good or expert skiers. This good/expert group is significantly (p<0.01) larger between injured off-piste skiers compered to injured skiers in total. 74.7% of the injuries were due to falls. The proportion of injuries due to collision with a solid object was significantly (p<0.01) larger between off-piste skiers (24.1 %) than injuries in total (3.8 %) in 2011. Collision with solid objects had also increased significantly (p<0.05) since 2001 when the percentage of total injuries was 12, 4 %. A significant increase in helmet use between injured people was observed from 2001 (22.5 %) to 2011 (84.3 %) (p<0.01). The number of head injuries has been stable throughout the period. CONCLUSIONS: There has been a significant reduction in the proportion of off-piste injuries in Hemsedal Skisenter from 2001 to 2011. The people who hurt themselves off-piste are more often good or expert skiers. Off-piste skiers/snowboarders are more prone to hit solid objects than the rest of skiers/ snowboarders in Hemsedal Skisenter. There has been a significant increase in helmet use in this resort throughout the period from 2001 to 2011, but no significant reduction in head injuries.