Background: Several researchers have reduced engagement in stereotypy in individuals with intellectual disability and deafblindness using interventions containing a punishment component. The purpose of our study was to examine whether we could produce reductions in stereotypy in an individual with Cornelia de Lange syndrome and deafblindness by using noncontingent and differential reinforcement only. Method: We used single-case experimental designs to examine the effects of noncontingent reinforcement alone and in combination with differential reinforcement of sitting on mouthing, tapping, and appropriate behaviour. Results: Noncontingent access to edible items reduced mouthing whereas access to tactile stimuli did not. Combining noncontingent access to tactile items with differential reinforcement reduced mouthing and tapping while strengthening appropriate behaviour. Conclusions: Antecedent- and reinforcement-based interventions were effective at reducing engagement in stereotypy in an individual with Cornelia de Lange syndrome and deafblindness without relying on punishment. However, more research is necessary to replicate our findings.