The OASIS project ("Old Age and Autonomy: The Role of Service Systems and Intergenerational Family Solidarity") analyses the informal and formal provision of help and support to the elderly in a welfare state comparative perspective. The focus of the project is on the relation between intergenerational family help and welfare state support. While the “substitution” hypothesis states that generous provision of welfare state services crowds out family help to older people, the “encouragement” hypothesis predicts the crowding in of family help, and the hypothesis of “mixed responsibility” predicts a combination of help and support by families and services. The OASIS data set is based on an age stratified random sample of the urban population (25-102 years) in Norway, England, Germany, Spain, and Israel (n=6,106). This data set allows the analysis of the interactions between societal micro and macro levels. Results show that total help received by the elderly is more extensive in welfare states with a strong infrastructure of formal services. Moreover, statistical controls for social structure, preferences and familial opportunity structures yield no evidence of any substantial crowding out of family help. These results support the hypothesis of “mixed responsibility”: In societies with well-developed service infrastructures, help from families and welfare state services act accumulatively; such mixes do not occur in familialistic welfare regimes.