Breast cancer is known to be associated with familial aggregation in the West. However, similar data has not been collected in a Chinese population. In a survey of 820 newly-diagnosed breast cancer patients treated in our centre from January 1989 through December 1994, 6.6% had a family history of breast cancer. This group presented at an earlier age and had a significantly higher proportion with the histological subtype of mucinous carcinoma. Although 31.5% of patients with a family history presented with early breast cancer, only 12.7% of those without familial breast cancer presented with early disease--perhaps reflecting a delay in consultation in women who are less aware of the disease. Our results suggest that the incidence of familial breast cancer in Chinese is much lower than it is in the West, and may partially explain the lower incidence of breast cancer found in our population compared with the West.