Over the last few years, there has been an enormous increase in the use of needle core biopsy (CB) for the histopathological characterisation of suspect lesions of the breast. The aim of this study was to verify the diagnostic reliability of CB by comparing the histological results obtained with the use of this technique with those obtained from the whole of the surgically resected specimen. We studied 198 out of 426 patients with clinically and/or radiologically suspect breast lesions. We found correspondence between the histological examination of the whole of the excised specimen and that of the CB in 94.9% of the cases of infiltrating carcinoma and in 71.4% of those involving ductal carcinomas in situ. The predictive value of CB was 98.9%, sensitivity was 96.1% and specificity 93.3%. These results confirmed that CB is an extremely reliable diagnostic tool in the definition of breast lesions.