The incidence of mycotic infections of the paranasal sinuses tends to increase with frequent use of antibiotics, anticancer drugs and steroids or prolonged survival of chronically debilitated patients. Seventeen cases of mycotic infections of the paranasal sinuses during a period of 8 years from January, 1980 to August 1987 were analyzed. The results were as follows ; 1) Out of 17 cases, 9 cases(53%) occurred in the 4th and 5th decades. 2) Mycotic infections of the paranasal sinuses occurred 2.4 times as frequently in female patients as in male patients. 3) The time intervals between the onset of symptoms and the first hospital visit was as follows : 5 cases between 6 and 12 months, 4 cases between 3 and 6 months, 4 cases within 1 month. 4) The chief complaints were nasal obstruction, purulent rhinorrhea, headache and postnasal drip. 5) Abnormal radiologic findings were hazziness of the involved sinus or sinuses in all cases and bony destruction in 1 case. There were 2 cases of bilateral involvement and 15 cases of unilateral involvement, of which 9 cases occurred in the right and 6 cases in the left. 6) The most common pathogen was Aspergillus(14 cases 82%). 7) Radical operation of the sinus or sinuses with adequate postoperative sinus irrigation was most effective in the treatment of mycotic sinusitis.