Background: Problems associated with psychiatric diagnoses could be minimized by identifying behavioural clusters of specific psychiatric disorders. Methods: Sixty persons with intellectual disability (ID) and behavioural problems, aged 12?55 years, were assessed with standardized Indian tools for intelligence and adaptive behaviour. Clinical diagnoses were conferred as per International Classification of Diseases--10th Revision (ICD-10) criteria. Subsequently Reiss Screen for Maladaptive Behaviors (RSMB) and AAMD Adaptive Behavior Scale-Part II were administered independently. Results: Aggression and rebellious behaviours were more common in affective disorders and personality disorders. Psychotic and paranoid features were significantly more in psychosis group. Those with behavioural problems had significantly low scores on the sub-scales of RSMB. Conclusion: RSMB and AAMD Adaptive Behavior Scale-Part II will be useful to identify behavioural clusters, which will complement clinical psychiatric diagnoses in individuals with ID.