Report of three cases of mucoepidermoid tumors with rare locations in laryngological areas (fundus of the tongue, retromolar trigonum, nasopharynx and sinuses). In two cases the tumors could be removed radically, the third case resulted in an extensive tumorous destruction of the right half of the face after a protracted course of the disease, as the consequence of which the patient died. With the aid of the literature on the subject, the location, clinical features, pathological anatomy and histology, origin, biological valence and the prognosis of mucoepidermoid tumors are discussed. It is generally agreed that they are optionally malignant tumors which can induce a locally infiltrating or destructive growth, show a tendency to recurrence and may lead to distant metastases. The recommended therapy is the radical exstirpation of the tumor.