The radiological observation of 360 cases of chronic maxillary sinusitis and histopathological study of 165 cases of Caldwell-Luc's operation, who visited the Otolaryngological department of Pusan Wallace Memorial Baptist Hospital from June 1982 to December 1983, were done as well as observation of annual incidence of chronic maxillary sinusitis from January 1973 to December 1983. The results were as follows : 1) The ratio of chronic maxillary sinusitis to all out-patients dept. patient was decreased annually and the average was 26.4%. 2) The ratio of male and female was 1.3 : 1 and the age distribution revealed 221 cases(66.4%) in the 5-24 year age group. 3) Bilateral maxillary sinusitis was seen in 290 cases(80.6%), and unilateral maxillary sinusitis in 70 cases(19.4%). Of 70 cases, 22 cases were seen in Rt. and 48 cases in Lt. 4) On the X-ray findings of chronic maxillary sinusitis, the diffuse homogenous density type was seen in 286 sides(44%), the mucosal thickening type in 227 sides(34.9%), the fluid level type in 79 sides(12.2%) and the polypoid type in 58 sides(8.9%). 5) In the view of duration of chronic maxillary sinusitis, 2-3 years was most frequent as 32.3%. 6) Of 360 cases, 218 cases were complicated nasal polyp, 147 cases with chronic hypertrophic rhinitis, and 105 cases with nasal septal deviation. 7) The histopathological classification of antral mucosa revealed edematous type(64 sides, 38.8%), infiltrating type(58 sides, 35.2%), fibrotic type(27 sides, 16.4%) and mixed type(16 sides, 9.7%) in 165 sides. There was no correlations between the X-ray findings and antral mucosal findings of chronic maxillary sinusitis.