This paper discusses the connections between basic services and social protection, focusing on health (including nutrition), education, water and sanitation, and safety, security and access to justice (SSAJ). It argues that good quality services in all four sectors can play an important role in reducing vulnerability whereas, conversely, poor quality and inaccessible services in these areas can be a cause of vulnerability. Much can be done through 'sectoral routes' to improve the accessibility and effectiveness of services for poor people. However, these measures are unlikely to be enough on their own and need to be complemented with specific 'social protection measures' that enable the poorest to access and benefit from key services. Most of these can be implemented through mainstream services; indeed, considering them as separate 'social protection' measures unhelpfully sets up a dichotomy between basic service provision and social protection. The need for special measures to ensure poor and marginalised people benefit fully from mainstream services is justified from a normative human rights perspective, which has human dignity and equality as fundamental values; it is based on the results of pilot or large-scale programmes that have sought to do so. However, for this review, no studies could be located which specifically compared the poverty and vulnerability-reducing effects of current sectoral investment programmes with particular 'social protection' measures aiming to enhance human development outcomes or service use. This paper concludes with suggestions for increasing the contribution of basic services to the social protection of poor and vulnerable people.