This paper examines the social support networks of older adults. Based upon the Kahn and Antonucci (1980) life course social support model, a national sample of adults aged 50 and older (N = 718) was interviewed, generating support networks consisting of an average of 8.9 members. The respondents were asked questions of the structural (e.g., age, sex, closeness, years known, proximity, and frequency of contact) and functional (number and type of supports provided and received) characteristics of their social networks. These characteristics and relationships are described in detail.