The 5-year survival of cancer of the breast in socioeconomically disadvantaged women is much too low because treatment is given for late stage disease. A screening mammography program at primary-care facilities for medically underserved women has markedly increased in situ and local stage of disease and decreased distant disease. This has produced an estimated 50% decrease in mortality and a significant decrease in treatment costs. Unacceptable delay from positive mammogram to biopsy and pathologic diagnosis remained, so a one-stop breast center was established to perform breast physical examination, screening mammography, biopsy, and pathologic interpretation at one site on one visit for optimal cost-effectiveness.