The purpose of the present work was to define some aspects (i.e. the influence of histological grading on prognosis and the possibility of an eventual hormone dependency) of adenoidocystic carcinoma, a highly controversial form of carcinoma still open to debate. A study is thus reported of 33 cases of adenoidocystic carcinoma of the head and neck seen from 1965-1985 at the E.N.T. Clinic of Ferrara. The individual histological samples were seen over a period of time by a single histopathologist who was not informed as to the patients' clinical progression. In this manner the diagnostic criteria was kept constant. Tumoral grading was then performed on the basis of the Marsh and Allen classification. The overall actuarial survival curves are presented according to site and grading. Besides confirming the already known data regarding the decrease in survival rate well beyond the fifth year, local recurrences and the frequency of lymph node and secondary metastases, the results indicate a direct relationship between grading and prognosis. In fact, overall survival decreases for the less differentiated forms while the frequency of local recurrences increases as does that of lymph node and systemic metastases. Furthermore, in 63.3% of the female patients a genital hormone dependent pathology was noted prior to the appearance of a salivary gland tumor. These observations would suggest that hormones may play a role in the genesis of adenoidocystic carcinoma.