This project was the first to collect data about the elderly population living in the community in Sao Paulo, Brazil. The main hypothesis guiding the study was that the social class of the elderly person is the basic determinant of well-being in old age. A multidimensional functional assessment questionnaire was developed, yielding information on five dimensions of the elderly person's functioning: socioeconomic status, physical health status, independence on the activities of daily living, mental health status, and social interaction. The sample was geographically stratified by social class using the sub-districts of Sao Paulo (administratively defined areas) as stratification units. Three sub-districts were selected and a total of 303 interviews were conducted. The results showed strong associations between living in the poor area, being a migrant, having a large family, living in a multigeneration household, reporting more chronic diseases, having more psychiatric disorders and perceiving less satisfaction with life in general. Although life in a multigeneration household was also associated with more availability of help in case of need, such living arrangement did not seem to compensate for the burdens of poverty. Some priorities for future research in the area are discussed, and the implications for policy making are outlined - the differences between the areas called for profound social changes if well-being in old age is to be a goal.