A numerous number of case-control studies have already demonstrated a certain extent of familial clustering for most human cancers. This is the first report of follow-up study with respect to familial predisposition to cancer. About 40 thousands women who participated in a cervical cancer screening program in 1977 were followed up until 1985 by using the population-based cancer registry. Cancer patients who were detected in the cohort population and their controls were compared for the family history of cancer and female reproductive history both of which had been recorded in a computer file beforehand. For large bowel cancer and breast cancer, positive effect of familial predisposition was observed, though not statistically significant.