The Working Group on Legislation, Legal Aspects, Cost-Effectiveness, and Barriers to Breast Cancer Screening addressed a heterogeneous group of issues, each of which has been shown to have an important influence on current rates of participation in breast cancer screening. At the beginning of the session an overview of the American Cancer Society-supported Miami Community Demonstration Project for Detection, Education, and Prevention was presented. Because the presentation included a detailed description of actual screening, diagnostic, and treatment costs, it served as a catalyst for a spirited debate on the assumptions and importance of cost-benefit/effectiveness/efficiency modeling. The discussion also generated the overriding theme for the working group session: how to assure low-cost, high-quality mammography for all women. One issue that was raised was the degree to which these analyses call into question the ultimate value of breast cancer screening since they tend to demonstrate large dollar costs for small numbers of cancers detected, years of life saved, and other outcome measures. The consensus of the group was that the value of screening transcended cost modeling findings: even though screening is costly, it saves women’s lives. However, it was also acknowledged that the conclusions of these models are highly dependent on the cost and benefit assumptions. Although many of these models are hypothetical, other analyses based upon ongoing projects have shown that in actual practice settings, the costs of screening can be substantially lower than average costs assumed by the models. Even though the ultimate value of screening for breast cancer does not depend on these analyses, the importance of cost effectiveness research was acknowledged, specifically the need to both refine models in terms of assumptions, outcomes, and economies of scale, and to better quantify the cost of early detection and treatment.