Despite various attempts at prevention, injury in downhill skiing continues to be a worrisome recreational problem. The purpose of this study was to test the effect of an instructional ski video on the behaviour and injuries of 763 downhill skiers. They were enrolled in two study groups, based on whether or not an instructional video had been shown in their bus on the way to a skiing resort. The video focussed on information regarding how to get started in downhill skiing and injury prevention. The outcome parameters, behaviour (binding test and adjustment), injury risk, type and consequence, were registered on the return trip 8 days later by a questionnaire. In the intervention group all outcome parameters changed significantly. The binding test was performed by 86% in the intervention group and by only 59% in the control group (P < 0.05). Adjustment of the bindings was done by 22% in the intervention group vs 14% in the control group. Regarding injury risk, 205 injuries were seen in 158 persons (20.7%) which is 26 injured skiers per 1000 skier-days and 33.6 injuries per 1000 skier-days. In the intervention group 16% of all skiers were injured vs 23% in the control group, yielding a reduction in injury risk of 30% (P < 0.05). Injuries caused by falls were seen in 12.6% in the intervention group vs 16.2% in the control group (P < 0.05). Injuries caused by collision were seen in 6% of the intervention group vs 12% in the control group (P < 0.05). The overall mean injury risk was 16 injuries per 1000 falls. Knee injuries made up 32.6% of the total. For inexperienced skiers the knee injury risk was significantly lower if the bindings had been tested (P < 0.05). Therefore, an instructional ski video can change the behaviour of downhill skiers and reduce the injury risk and consequences significantly.