Between 1972 and 1987, the authors prospectively evaluated all 5701 injuries which were reported to the injury clinic operating in the base lodge of a ski area in northern Vermont, USA. During that time approximately 1,690,000 skier visits were estimated to have occurred at the ski area. The total injury population was divided into 28 groups and sub-groups and examined by regression analysis for long term trends. Among upper body injuries, only lacerations showed a positive improvement. Among lower extremity injuries, virtually all injuries below the knee improved dramatically, some groups by more than 80%. Knee injuries, although improved as a group, showed a marked 2.7-fold increase in serious (third degree) sprains usually involving the anterior cruciate ligament. Clavicular fractures were the only upper extremity injury which increased significantly in incidence.