Percutaneous large core biopsy of the breast with a 14-gauge needle, supported by sonographic and mammographic procedures, shows a high degree of safety during the collection for benign and malignant lesions. All malignant diagnoses (B 5) with a portion of 44% (267/604) were confirmed surgically, whereby the typing with 79% and grading with 58% were congruent. In 3.3% (20/604), there was uncertainty (B 3 and B 4), with the necessity for further clarification by open biopsy. This was supported by the fact that in 10/16 operated cases carcinoma was found. In the B 2-category, with a portion of nearly 44% (264/604), four cases of cancer were verified--not due to a wrongly negative histology but to non-representative material. In 8.8% (53/604), a questionable representative histology (B 1) occurred, but no cancer was found after surgical intervention (n=7). The indication for surgery is not only the punch biopsy result, but additionally negative histology and suspect or malignant clinical findings.