Fibroma of the maxillary sinus is extremely rare. The first case of antral fibroma was reported in 1927 by J. Harper. A 15-year-old Korean boy visited our hospital on May 15, 1969. He complained of a mass in left maxillary region, which was not painful and had been progressively increasing in size for 15 months. The initial physical examination revealed a hard, child's-fist-sized mass in the left maxillary region, protrusion of the left maxillary bone into gingival region, and narrowing of nasal cavity due to pressure in its lateral wall. The histopathological examination of the biopsy specimen taken from the left maxillary sinus through Caldwell-Luc approach revealed ""fibroma."" The removal of the tumor by lateral Rhinotomy was an effective treatment in this case.