Triple negative breast tumors are described by the lack of immunohistochemical expression for hormone receptors (ER and PgR) and Her2 neu. The immunophenotype is, in general,associated with young age and high biological aggressiveness,its frequency in the literature ranging from 10 to 20%. In our study we performed a retrospective classification of triple negative breast cancers in order to show the large spectrum of lesions that can embrace this very special phenotype.Clinicopathological parameters evaluated included age, tumorsize and macroscopic appearance, histological subtype and association with in situ component, the degree of tumor differentiation (nuclear pleomorphism, mitosis count, the formation of tubules), presence of lymph nodes or distant metastases. Triple negative breast cancers represent a particular subtype of tumors but their, now famous, aggressiveness applies only to some histological subtypes. It is very important to correlate the histological features and the phenotypical expression.