Musculoskeletal injuries represent an adverse event of strenuous physical activity. The aim of the present study was to identify pretraining factors that may predispose to such injuries. Risks of injury according to age, body composition, previous physical activity, physical fitness, use of smokeless tobacco (moist snuff) and smoking habits were determined in a population of 480 male conscripts in the army. Data were obtained by questionnaire, height and weight measurements, and from a 3000-metre run test prior to a 10-week period of basic military and physical training. Injuries were registered by doctors attached to the training camp. Every fourth conscript sustained one or more musculoskeletal injuries during the training period. Low back pain, overuse knee injuries, Achilles tendinitis, and sprains of joint capsules or ligaments were the most frequent diagnosis groups. Subjects aged 22 years and more, the least active persons before call-up, those who thought they were less fit than the average, the slowest one-third in the 3000-metre run test, smokers of more than 10 cigarettes a day, and snuff-takers suffered more injuries according to univariate analyses. Multiple logistic regression analysis showed that age, self-assessed physical fitness and snuff-taking were mutually independent risk factors of high statistical significance.