The use of mammography has resulted in 1464 breast biopsies for nonpalpable abnormalities at the University of Virginia in the 10 years 1980 to 1989. Two hundred sixty-four cancerous lesions (18%) were found. One hundred seventy-eight of these (67%) were in situ lesions. Invasive cancer (86 of 264 lesions or 33%) forms the basis for this report. Mammographic findings leading to biopsy were a mass in 61 of 86 cases (71%), microcalcifications in 23 of 86 (27%), or both in 2 of 86 cases. Histologic subtypes were infiltrating ductal (63 of 86), infiltrating lobular (14 of 86), and other infiltrating (9 of 86). Mastectomy was performed in 71 of 86 lesions (82%), lumpectomy/radiation in 14 of 86 (16%), and lumpectomy alone in 1 of 86 lesions. Division of the tumors into size with nodal status revealed 19 of 86 lesions (22%) less than 0.5 cm with 0 of 14 positive nodes. Thirty-nine of eighty-six lesions (46%) measured 0.6 to 1.0 cm with 10 (26%) positive nodes. Twenty-eight of eighty-six lesions (32%) measured more than 1.0 cm with 8 of 28 (28%) positive nodes. Nodal status is unknown for eight patients. Overall 18 of 78 lesions (23%) had positive nodes. Median follow-up is 44 months. Disease-free survival rate is 92% (79 of 86 patients) and overall survival rate is 94% (81 of 86 patients). Six of seven recurrences occurred in node-positive patients. For those with negative or unknown nodes, the disease-free survival rate is 98% (67 of 68 patients). These findings emphasize the benefit of early detection of breast cancer through the use of mammography.