This paper tests assumptions often made by policy makers and practitioners that networks of family, friends, and neighbours are able to provide sustained care to frail elderly Canadians. Using national survey data, we examined characteristics of the care networks of 1,104 seniors living with a long-term health problem. Care networks were found to vary considerably in size, relationship composition, gender composition, age composition, and proximity, and these network characteristics were found to help explain variations in the types and amounts of care received. As a result, network characteristics that might place seniors at risk of receiving inadequate care (including small size and higher proportions of non-kin, male, and geographically distant members) were identified. These risk factors appear to be poorly reflected in most existing policy.