Barriers to mainstream health and social care services for London's minority ethnic communities include a complex array of poorly organised and delivered services, inadequate communication services for non-English speaking groups, direct staff insensitivity to users' cultural and religious needs, and institutionalised barriers that perpetuate discriminatory behaviour and poor practices. This study was commissioned by the King's Fund and the London NHS Region to map the range and scope of health advocacy providers for black and minority ethnic communities across London, and to develop a clearer understanding about how the effectiveness of such services could be assessed. The study aimed to provide valuable baseline information on which strategic investment decisions could be made regarding options to support and develop health advocacy services and health advocates themselves.