ABSTRACT Longitudinal ethnographic data of 49 families in the San Antonio site of the Three City Study illustrate the ways in which families that remain on welfare differ in important ways from families in which the mother is employed. Families that remain on welfare experience substantial health and emotional problems; have limited access to informal supports; and are headed by mothers with little education or prior work experience. These ethnographic findings have important implications for survey-based studies in which the selection problems can easily affect results when families on welfare are compared to wage-reliant families.