Children with Down syndrome are at an increased risk for engaging in challenging behaviour that may present problems within community, leisure, and educational settings, and, in many instances, precludes them from accessing these environments. Factors contributing to the occurrence of challenging behaviours include characteristics associated with the Down syndrome behavioural phenotype, increased incidence of illness and sleep disorders, and the way in which individuals in their environment respond to their behaviours. In this paper we describe the use of behaviourally based intervention strategies to address some of the specific challenges often seen in young children with Down syndrome. Through a series of case studies, the effectiveness of evidence-based interventions addressing challenging behaviour is demonstrated. (Contains 3 figures.)