Rationale, aim and objectives This paper describes the results of the process evaluation of a physical activity programme for people with intellectual disabilities (ID), including information about the concepts 'fidelity', 'dose delivered', 'satisfaction' and 'context'. Methods Qualitative and quantitative methods among participants and programme leaders were used. Results The programme was well accepted, feasible and applicable to ageing people with ID. It was successfully implemented in terms of fidelity and dose delivered, although differences between day-activity centres were observed. Conclusions The hampering factors that are revealed in this study and the facilitating activities that were part of the implementation plan may be used by care provider services for (ageing) people with ID and other groups of people with cognitive and/or physical deficits, such as frail elderly people or people with dementia when developing and or preparing implementation of health promotion programmes.