Background: A training package for staff working with clients presenting challenging behaviour was developed to (1) increase their knowledge regarding challenging behaviour, and (2) to improve the quality of physical intervention techniques. The latter aim was intended to reduce staff anxiety about dealing with incidents and limit physical risk of injury to both clients and themselves. Materials and Methods: Sessions concerning theories of challenging behaviour were combined with physical intervention training. Effectiveness was assessed using knowledge questionnaires and observation of staff skills. Training effectiveness was tested in a pre-post-test control group design. Results and Conclusions: The training program proved to be effective. Staff knowledge of challenging behaviour and the quality of physical intervention techniques increased significantly. Scores remained above pre-test levels at follow-up. Staff members evaluated the training positively.