Background: Because of the problems measuring subjective well-being in people with severe and profound intellectual disabilities, there are no studies to date which explore the factors contributing to the subjective well-being in these groups. We wanted to explore the client and service characteristics contributing to the subjective well-being of persons with severe and profound intellectual disabilities, as measured by the MIPQ (Ross & Oliver, 2003). Materials and methods: The MIPQ was completed for 360 persons with severe or profound intellectual disabilities by a member of the direct support staff. They also provided us with information on client, service and informant characteristics. Results: We found that the subjective well-being of persons with profound intellectual disabilities was lower than the subjective well-being of people with mild, moderate or severe intellectual disabilities or people without disabilities. Client and informant characteristics but no service characteristics were found to have an influence on the subjective well-being of people with severe and profound intellectual disabilities. Conclusion: As it is important for policy making to identify residence service and staff factors related to subjective well-being of persons with severe and profound intellectual disabilities, further research should try to identify these factors, taking in account the client characteristics that are found to be related to subjective well-being in this study. (Contains 4 tables.)