Standard radiologic examinations of breast duct lesions can give only indirect information. Mini-endoscopy with a breast ductoscope of only 0.55 mm offers direct visualization of the lesion and helps in the decision to perform or avoid exploratory breast tissue resection. We used a LaDuScope (PolyDiagnost, Pfaffenhofen, Germany) with a 0.55- or 0.95-mm outer diameter and a 75-mm working length from October 2003 through July 2004 on 11 women (average age of 48.3 years [range 36-69 years]) with suspicious nipple discharge. The optics have zero-degree direct view, 70-degree field vision, and 3000 or 6000 pixel resolution. Breast ducts and walls could be easily inspected; and irrigation of breast ducts, aspiration, and use of cytology brush were possible under visual control. We had no intraoperative or postoperative complications. The new procedure of mini-ductoscopy is feasible, safe, and helpful as an additional ambulatory diagnostic method for visual inspection of breast ducts. This instrument demonstrates the latest advances of technology and a trend toward less-invasive diagnostics for breast duct lesions.