Placed in the context of broader discussions and developments about service user involvement in research and evaluation, this paper looks at the role that user involvement research may play in health inequalities research. It examines the pressures for and against such user involvement research, its different expressions and ideological relations, and what particular contribution it may have to offer in researching health inequalities. In considering how it may help in developing substantive understandings of these issues and the role it may play in the future, particular attention is paid to the issue of enabling the diverse involvement of service users in order not to reinforce existing exclusions and barriers in research, policy and practice.