The aim of this study was to analyse the clinical, histological and immunohistochemical prognostic factors of a large series of adenoid cystic carcinoma, using univariate and multivariate survival analyses. All cases of head and neck ACC (n = 129) treated in a single institution in Brazil, between 1955 and 1997, were selected for the study. Univariate survival analysis revealed that age older than 45 years (p = 0.04), period of complaints inferior to 18 months (p = 0.007), presence of paresthesia (p = 0.04), T stage (p = 0.01), N stage (p = 0.04), M stage (p < 0.001), clinical stage (p = 0.003), solid histological type ( p< 0.001), presence of residual tumor (p < 0.001) and expression of p53 (p = 0.08) correlated with a poor prognosis. In the multivariate survival analyses, clinical stage, solid histological subtype and increased expression of p53 were independent significant prognostic factors. According to our findings, clinical stage, solid growth pattern and expression of p53 were the most important prognostic factors in patients with ACC.42139-46