The aim of this retrospective clinical study was the analysis of histologic findings of nonpalpable breast lesions managed by open surgical biopsy. A series of 630 women underwent 664 preoperative localizations of nonpalpable, mammographically detected breast lesions during the last 10-year period. Indications for biopsy were (1) clustered microcalcifications, (2) solid mass, and (3) radiologic parenchymal distortion. The lesions were localized preoperatively using hook-wire methods, and all biopsies were performed under general anesthesia. Histopathology revealed carcinoma in 172 (25.9%) cases; noninvasive in 114 (66.3%) cases and infiltrating in 58 (33.7%) cases. The highest malignancy rate was found in cases with microcalcifications (112 carcinomas out of 323 cases, 34.7%). Lymph node invasion was present in 25% of patients with invasive cancers. The hook-wire localization of nonpalpable breast lesions is a simple, accurate and safe method for detection of early breast cancers. Frozen section is feasible and accurate in the majority of these lesions, and therefore, diagnostic and therapeutic one-step surgical procedures could be performed.