The incidence of primary carcinoma of the breast in Hong Kong has been rising. A screening team including radiologists, breast surgeons, cytopathologists, a full-time gynaecologist and mammographers was set up at Kwong Wah Hospital. The screening method includes a clinical breast examination (CBE) and two-view mammography. The target age group is 40-70. A total of 13,033 women were screened from March 1993 to March 1995 and 8504 mammograms were performed. A double reading system was used, with an experienced mammographer as the first reader. The films were then read by radiologists and were reported. All abnormal films and normal films with palpable masses or clinical symptoms were reviewed in a weekly meeting. A total of 113 biopsies were performed including 86 stereotactic-guided fine needle aspirations (FNA) and 27 stereotactic-guided hook-wire biopsies. Four FNA showed malignant cells and another five showed suspicious cells. Eleven hook-wire biopsies showed carcinoma. The benign to malignant ratio of the hook-wire biopsies was 16:11 (< 1.5). The total number of carcinomas disclosed was 42, and 16 of these were not palpable. Four palpable tumours were not detected by mammography. The overall carcinoma of the breast detection rate was 4.94/1000, with a rate of 4.61/1000 for the 40-49-year age group and a rate of 6.46/1000 for the over 50 years of age group. The incidence of ductal carcinoma in situ plus T1 tumours was 2.82/1000.