Introduction: Sinonasal malignancies are uncommon neoplasms with several histological subtypes. These malignancies have a poor prognosis and, because of the nonspecific nature of the symptoms, most patients are diagnosed late when the disease is already at an advanced stage. Therefore, most sinonasal malignancies tend to be treated with surgery and postoperative radiotherapy. Understanding the incidence and prevalence of clinical symptoms, pathology, diagnosis, and subsequent prognosis of the disease is important for early diagnosis. Materials and Methods: Medical records of patients with a confirmed diagnosis of sinonasal malignancy in a tertiary referral center from ۱۹۹۸ to ۲۰۰۹ were retrospectively investigated by chronological examination. Information relating to symptoms, pathology, and treatment of patients were collected from the checklists and used to generate tables and graphs, while descriptive statistical tests were used to compare data. Results: The records of ۶۹ patients were examined, including ۴۵ (۶۵.۲%) male and ۲۴ (۳۴.۸%) female patients with a combined mean age of ۵۴.۰۷±۱۶.۰۴ years. Twenty-one patients (۳۰.۴%) were aged less than ۴۵ years and ۴۸ (۶۹.۶%) were more than ۴۵ years of age. The most common symptom was facial swelling in ۴۶ (۶۶.۶%) patients and the most common kind of tumor was squamous cell carcinoma in ۲۸ (۴۰.۶%) patients. The primary location of the tumor in most patients was the maxillary sinus (۵۴ patients; ۷۸.۳%). A majority of patients present in advanced stage (stage III or more) with intraorbital (۳۹.۱%) or intracranial (۴.۳%) involvement, or regional lymphatic (۲۸.۹۹%) or distance metastasis (۷.۲%). The most common treatment was surgery (۱۷ patients; ۲۴.۶%). Conclusion: Due to their nonspecific symptoms, most sinonasal malignancies are diagnosed at an advanced stage of the disease. Therefore, all patients with nonspecific symptoms, especially older males, should be evaluated for sinonasal malignancies in order to eliminate this diagnosis.