Breast carcinoma continues to be the most common cause of death due to malignancy for women in Canada. The Screening Mammography Program of British Columbia, the first provincial screening program in Canada, was established in 1988 with funding from the Ministry of Health to diagnose the disease as early as possible. The program has grown rapidly, increasing from 7,100 examinations in a pilot project in 1988 to 89,390 examinations between April 1, 1992 and March 31, 1993 for a cumulative total of 201,937 examinations of 128,325 women, and it now offers free screening mammography throughout the province. The program has maintained quality control standards and low cost per mammogram while developing different operational models for the differing requirements of the various areas of the province. Similar proportions of women older or younger than age 50 have favourable characteristics such as small size of tumor (median: 15 to 16 mm) and negative lymph nodes (86% to 89%).