Evidence for the genetic basis of cancer has increased in recent years, and thus, assessing familial aggregation may play an important role in epidemiologic studies. To assess the degree to which family history variables are collected in cancer case-control studies, the authors conducted a literature review of studies published in six journals during 1982-1984. Only 25% of these included a family history component. The authors review some of the literature in favor of inclusion of family information and argue for its routine collection in cancer case-control studies.