Abstract: Introduction: Malignant nasosinusal tumors represent about 3 % of the cancers of the head and neck region and 0,8% of all human cancers. They are usually diagnosed in advanced stages, with non-specific clinical presentation at the beginning. Purpose: To study these tumors in relation to prevalence, patients's characteristics, localization and hystologic types. Material and Methods: The authors undertook a retrospective research in the Otolaryngology Department of Clinics Hospital - University of São Paulo Medical School - which included 98 patients with malignant nasosinusal neoplasms diagnosed in the latest 15 years. Most of the cases were males (62 patients), the majority within the age range from 40 to 70 years old (55,1%). Carcinoma was the most frequent hystologic type, affecting 62,2% of the patients, followed by the neural tumors (11,2%), sarcomas (9,2%), lymphomas and plasmocytomas (5,1%) and vascular tumors (3,1%). Results: The main complaints were nasal obstruction (61,2%), epistaxis (40,8%), facial deformity (39,2%), facial pain (39,2%) and nasal infection (23,9%). The most common sites affected were the nasal fossa (67,3%), the maxillary (61,2%) and ethmoidal sinuses (50%). It was found that in 72,4% of the cases the tumor involved two or more nasosinusal sites, showing great extension at time of diagnosil. Conclusion: malignant nasosinusal neoplasms are rare and initial presentation shows non-specific signs, misleading the diagnosis; therefore, they must be excluded in cases of suspicion of chronic nasosinusal infection.