In this paper recent studies of the relationships between social networks and mortality among older people are reviewed. Although a large amount of research effort has been expended on identifying and explaining such relationships, many studies have focused predominantly on those in middle age groups and very few have included sufficient numbers of older old people to allow separate analyses. Moreover, although relationships between various indicators of social support, participation and mortality have been demonstrated, this finding is not universal and considerable uncertainties remain about the strength of any such association, how it may vary between age and social groups and how it operates. In part, these uncertainties reflect the wide range of conceptual definitions of social networks or social support, methodologies and data sets used to address the issue.