This study was performed for the purpose of clinicopathological study of the chronic maxillary sinusitis. The mucous membrane of maxillary sinuses in 88 cases that received Caldwell-Luc's operation during the period from March 1978 to May 1981 in Dept. of Otolaryngology, Eul Ji General Hospital. The results were obtained as follows: 1) The pathological classification revealed edematous type (12 case, 13.7%), fibrous type (28 case, 31.8%), infiltrative type (4 case, 4.5%), mixed type (44 case, 50%) in 88 cases. 2) The most frequent change in glands are mild degree in edematous type (36.3%), mild degree (66.7%) in infiltrative type, normal or decrease (60%) in fibrous type, normal decrease (50%) in mixed type. 3) The most frequent change on blood vessels are mild degree (60%) in fibrous type, moderate change (66.6%) in edematous type, severe change (50%) in mixed type, moderate change (50%) in mixed type. 4) The most frequent degree of cell infiltration are moderate infiltration (75%) in edematous type, mild infilration (33.3%) in fibrous type, severe infiltration (100%) in infiltrative type, severe infiltration (60%) in mixed type. 5) The cells infiltrated are lymphocyte, plasma cell, neutrophile, eosinophile. Most cells infiltrated are lymphocyte and plasma cells, lymphocytes and plasma cells are observed in all slides. 6) In the age incidence, the highest incidence revealed between 15 to 19 years of age (37 case, 42%), in sex distribution 50 cases (56.8%) were males and 38 cases (43.2%) were females. 7) In the relation of type of mucous membrane in maxillary sinus to duration of illness, 2 to 4 years duration (48 case, 54.5%) is most frequent. 8) Chief complaints of chronic maxillary sinusitis were Nasal stuffiness and obstruction, Nasal discharge, Headache in order.