Background: Patient experience of those accessing mental health services has been found to be different between ethnic groups. Although the needs of people with intellectual disabilities (ID) from different ethnic communities are being increasingly recognised, little has been published about their experiences of mental health services. The aim of this study was to establish whether there are any differences in the experiences of people with ID and mental health problems from two ethnic communities in South London. Method: A two-round Delphi process was utilised. White British and Black or Black British service users from a specialist community-based mental health service for adults with ID completed a specially compiled questionnaire. Statements on participants' experiences, including satisfaction with care, staff members' attitudes, cultural awareness and level of support, were rated using a Likert scale. Results: Twenty-four out of 32 participants (75%) completed both rounds of the Delphi consultation. Consensus ([greater than or equal]80% agreement with the group median) was reached for 20 items in the White group and five items in the Black group. All responses that reached consensus were positive about the services that were being received. The Black group were less positive about a range of their experiences, including the use of medication. Conclusions: People with ID from two ethnic groups were able to successfully complete a Delphi consultation regarding their experiences of mental health services. Broad consensus on positive experiences of services was reached in the White group but not for the Black participants. (Contains 4 tables.)