BackgroundIntensive support teams (ISTs) are recommended for individuals with intellectual disabilities who display behaviours that challenge. However, there is currently little evidence about the clinical and cost-effectiveness of IST models operating in England.AimsTo investigate the clinical and cost-effectiveness of IST models.MethodWe carried out a cohort study to evaluate the clinical and cost-effectiveness of two previously identified IST models (independent and enhanced) in England. Adult participants (n= 226) from 21 ISTs (ten independent and 11 enhanced) were enrolled. The primary outcome was change in challenging behaviour between baseline and 9 months as measured by the Aberrant Behaviour Checklist-Community version 2.ResultsWe found no statistically significant differences between models for the primary outcome (adjustedβ= 4.27; 95% CI −6.34 to 14.87;P= 0.430) or any secondary outcomes. Quality-adjusted life-years (0.0158; 95% CI: −0.0088 to 0.0508) and costs (£3409.95; 95% CI −£9957.92 to £4039.89) of the two models were comparable.ConclusionsThe study provides evidence that both models were associated with clinical improvement for similar costs at follow-up. We recommend that the choice of service model should rest with local services. Further research should investigate the critical components of IST care to inform the development of fidelity criteria, and policy makers should consider whether roll out of such teams should be mandated.