Mycotic infection of the paranasal sinuses may rarely occur as a paranasal sinus disease. However, with the advent of therapy with antibiotics, steroid hormones, antifungal agents and radiation, the incidence of the infection seems to have increased recently. The disease is characterized by a wide range of initial symptoms and should be considered as a possible diagnosis in case of sinusitis refractory to routine therapy. A clinical study was performed with 7 cases which were diagnosed as mycotic infection of the paranasal sinuses and treated at the Seoul National University Hospital and 9 cases from references. The results were as follows ; 1) Of total 16 cases, 6 cases (37.5%) were in the age between 30 and 39. The mycotic infection of the paranasal sinuses occurred approximately 2.2 times more commonly in the female patients than the male. 2) The incidence has increased in the last three decades. 3) The interval from the first symptom to hospital visit was as follows : 5 cases within 1 month, 4 cases between 4 and 6 months. 4) Most frequent clinical manifestations were nasal obstruction, headache, purulent rhinorrhea, bloody rhinorrhea, facial pain and postnasal drip. 5) Abnormal radiologic findings were clouding of the involved sinus or sinuses in all cases, and bony destruction in 4 cases (25.0%). 6) Aspergillus was the most common pathogen (14 cases, 87.5%). 7) Radical operation of the involved sinus or sinuses, adequate aeration, drainage of the sinus and/or massive antibiotics were successful.