BACKGROUND When compared to the general population, persons with an intellectual disability have lower life expectancy, higher morbidity, higher rates of unmet health needs, and more difficulty finding and getting health care. Organisational interventions are used to reconfigure the structure or delivery of health care services and may prove useful to decrease the noted disparities. OBJECTIVE To assess the effects of organisational interventions for the mental and physical health problems of persons with an intellectual disability. METHODS We searched the Cochrane Effective Practice and Organisation of Care Group specialised register (no year restriction), MEDLINE, EMBASE, CINAHL, other databases from January 1990 to April 2006 reference lists of included studies, and we consulted experts in the field. METHODS Randomised controlled trials, controlled clinical trials, controlled before and after studies and interrupted time series of organisational interventions aimed at improving care of mental and physical health problems of adult persons with an intellectual disability. METHODS Two review authors independently extracted data and assessed study quality. Missing data were requested from authors of included studies. RESULTS Eight studies met the selection criteria: six were randomised controlled trials, one was a controlled before and after study, and one was an interrupted time series. In general the studies were of acceptable methodological quality. The included studies investigated interventions dealing with the mental health problems of persons with an intellectual disability, none focused on physical health problems. Three of the studies identified effective organisational interventions and five showed no evidence of effect. Only two studies were similar enough to analyse using a meta-analysis. In the pooled analyses 25 participants received assertive community treatment and 25 received standard community treatment. Results from measures of function, caregiver burden and quality of life were non-significant. CONCLUSIONS There are currently no well designed studies focusing on organising the health services of persons with an intellectual disability and concurrent physical problems. There are very few studies of organisational interventions targeting mental health needs and the results of those that were found need corroboration. There is an urgent need for high quality health services research to identify optimal health services for persons with an intellectual disability and concurrent physical problem.