A total of 395 male infantry recruits were evaluated in a prospective study of possible risk factors for overexertional back pain and the efficacy of drug treatment regimens for this syndrome. Recruits were classified into subgroups of lumbar or thoracic, and paraspinal or spinous process pain. Recruits were divided into three treatment groups: Ibuprofen, Paracetamol, and no drug treatment. Of the recruits, 18% were diagnosed as having overexertional back pain during the course of 14 weeks of training. By multivariate analysis low body mass index was found to be a risk factor for overexertional lumbar pain (p = 0.005) and increased lumbar lordosis a risk factor for overexertional thoracic pain (p = 0.005). Of recruits with overexertional back pain, 65% were asymptomatic by the end of basic training. There was no statistically significant difference between cure rates according to treatment groups.