The objective of this study was to investigate possible relationships between the incidence of sports injury and the existence of body mechanics defects in players of various codes of football. Injuries were recorded prospectively over a 24 month period. Fifteen aspects of body mechanics were evaluated at the start of the study using a specially developed photogrammetric technique known to have high reliability and sensitivity. It was found that subjects who suffered from ankle injuries had lower mean scores for ankle mechanics than the non-injured players. Knee injuries were found to be associated with lumbar lordosis and sway back. Subjects who suffered from muscle strains had a higher incidence of lumbar lordosis, sway back and abnormal knee inter-space. Back injuries were associated with poor shoulder symmetry, scapulae abduction, back asymmetry, kyphosis, lordosis and scoliosis. Subjects who suffered from two or more injuries had lower overall body mechanics scores than the other subjects. In general, it was found that the incidence of ankle, back, knee and muscle injuries was influenced by the presence of defects of body mechanics. These results suggest that intervention to improve body mechanics would be likely to reduce the incidence of sports injuries in football.