This article provides an overview of measures for assessing the importance of social relationships to the outcome of illness in the elderly. Review of the evidence associating social relationships with the variability in health outcome emphasizes the need for separating social relationships into three components: Social network structure and composition; Type and amount of social support provided through the network; and, perceived adequacy of the social support. Because of physical and social changes during the life cycle, care must be exercised in selecting and interpreting social relationship measures for use with the elderly. Available measures relevant for assessing the three components of social relationships in the elderly are described.