A family diagnosed as cancer family syndrome because endometrial cancer was found in a member of this colorectal cancer-prone family was reported. The fact that uterine (endometrial) cancer was found in a family member during the serial follow-up of this family shows that there is no more than a difference of time between familial colorectal cancer and cancer family syndrome. The clinical significance of the familial cancer aggregation would be an important clue in the early detection of another new cancer in the family.