Survey data collected from a random sample of the Danish population in the first phase of a research investigation of self-care behavior are discussed. Self-administered postal questionnaires were used to obtain data on behavioral responses to common illness conditions. Information was obtained from 1,462 persons regarding care of 3,100 illness episodes. Log-linear analyses of multiway frequency tables were used to examine the effects of sociodemographic and attitudinal variables on the illness responses. Age, sex, perceived health status, and a reliant attitude toward physicians were the more important variables related to the illness behaviors. Interactions among these variables suggest directions for productive research into the factors shaping responses to illness. Income and social class, among respondents in relation to differences in activity levels maintained while ill suggest that some people may have limited options for caring for themselves during illness.