A total of 31 patients surgically treated for salivary mucoepidermoid tumor had a comprehensive follow-up. Two groups were classified as: 16 with favorable outcome (no recurrence or late recurrences at 5 yr postoperatively and still alive; 15 with poor outcome (local recurrences before 5 yr, metastases, lethal evolution in 11 cases). We evaluated nucleolar organizer in every case, using AgNOR count. The AgNOR count seemed better than histologic criteria for establishing the prognosis of mucoepidermoid tumors. It correlated significantly with the clinical course: a high count was principally found in lethal forms, low counts (less than 1.8) were always detected in patients with a good outcome.