Mucoepidermoid carcinomas (MEC) of the major salivary glands from 48 patients who received their treatment at a single institution were studied for prognostic indicators. Uni- and multivariate statistical analyses were performed on several clinicopathologic factors and also on flow cytometric (FCM) DNA content data of the carcinomas. Clinical prognostic factors associated with decreased survival included age > 60 years (P = 0.01), male gender (P = 0.002), symptoms at diagnosis (P = 0.03), stage of disease (P < or = 0.0001), type of surgery (P = 0.0006), and recurrence (P = 0.0001). Histopathological prognostic factors associated with decreased survival included MEC tumour grade (P = 0.0001), tumour size > 3.0 cm (P = 0.02), lymph node involvement (P = 0.0004) and positive surgical margins (P = 0.007). DNA FCM factors associated with decreased survival included aneuploid tumours (P = 0.08) and proliferative activity (S+G2M > 5%, P = 0.07). Multivariate analysis indicated that histological grade, proliferative activity, symptoms at diagnosis, clinical stage of disease and type of surgery were significant (P < or = 0.05) prognostic/survival factors in the biological assessment of this neoplasm.