Health screening has been shown to have beneficial effects on health outcomes in adults with intellectual disability. However, the nature of the population, which makes it difficult to recruit, has meant past studies have been relatively small and effect estimates unstable. This study conducted a pooled analysis of two randomised trials and one cohort study, containing a total of 795 participants. Use of a simple, low-cost screening tool produced substantial increases in health-promotion and disease-prevention activity, when compared with usual care.