Of about 8500 women with a minimum age of 30 years who had a breast examination at our Outpatient Clinic from April 1982 to March 1983, we found in 286 cases a clinically evident carcinoma, and in 534 cases an apparently benign or suspect solid lump. All 534 of these cases were subjected to the triplet clinical, mammographic and cytologic diagnostic investigation by needle aspiration within 1 to 4 days. The clinical judgment was based on a method of scoring of the characters of 9 physical features (Clinical Diagnostic Index) in use at our Institute. The results of the examinations were grouped into 5 categories: 1) certain benignancy or negativity of the examination; 2) probable benignancy (excluding the cytologic examination); 3) probable malignancy; 4) certain malignancy; 5) nonevaluability of the examination (excluding the clinical examination). Except for 80 cases with collectively negative examinations which were clearly or completely regressed at the control within 2 months, all the others were subjected to surgery. On the basis of the histologic examination (or if regression occurred), 284 of the 534 lumps examined were found to be benign or nontumoral, whereas the other 250 (47%) were carcinomas. Of the latter, 57% were not more than 20 mm in size, whereas in 67.6% there was no microscopic evidence of axillary metastases. Sensitivity of the clinical, mammographic and cytologic examinations was 0.79, 0.76 and 0.72, respectively; specificity 0.71, 0.75 and 0.94, respectively, and the predictive value for malignancy of the positive response of the three examinations 0.71, 0.75 and 0.93, respectively. The use of the diagnostic triplet demonstrated an overall sensitivity of 0.95, specificity of 0.59, and a predictive value for malignancy of 0.98 and 0.93 for benignancy. These results confirm the usefulness of the systematic use of the diagnostic triplet in solid breast lumps of over thirty aged women for the early detection of cancer.