Since back injury is the largest workman's compensation claim in most industries, the relationship between selected personal characteristics and back injury in hospital nursing personnel were studied. The sample included 64 female nursing personnel, half back injured and half not. Demographic: Workers were more likely to be back injured if they were older, worked longer on nursing units requiring frequent lifting, had family members with back problems, and had family members whose back problems began at an early age. Physical: The back injured had less muscle flexibility, less keen proprioception, and greater unequal leg length. Life style: Back injured were more vulnerable to frustration and stress overload (overstimulation), smoked more cigarettes, spent fewer hours exercising, and rated their physical condition lower. The variables with the greatest discriminatory power to predict back injury were a sense of overload, muscle flexibility, proprioception, family history of back problems, difference in leg length, years of risk in nursing practice, and smoking.