Background: An important question in community living is what factors influence the extent to which staff provide "active support". Methods: Engagement, care practices and a range of staff and organizational characteristics were studied in 72 residential homes serving 359 adults with intellectual disabilities. Managers in 36 settings were trained in person-centred active support (PCAS). A group comparison design and multivariate analysis was used to investigate the relationship between variables. Results: The PCAS group showed more active support, assistance, other contact from staff and engagement in meaningful activity but no difference in choice-making or assessment of participation in activities of daily living. The PCAS group had more staff with a professional qualification, were more likely to think that challenging behaviour was caused by lack of stimulation, had attitudes more in line with a policy of community care, rated most care tasks as less difficult, and were more organized to deliver active support. The comparison group were more likely to think that challenging behaviour was learned negative behaviour, showed more teamwork and were more satisfied. Multivariate analysis identified a range of staff and organizational variables associated with engagement and active support. Conclusions: The results suggest that some variables which have not hitherto been studied in relation with active support are associated with it. Professional qualification, knowledge and experience appear to be important as do some staff attitudes, clear management guidance, more frequent supervision and team meetings, training and support for staff to help residents engage in meaningful activity.