A survey on pneumonic lungs and its histopathological changes of the slaughtered pigs from the southern area of Chungbuk province was carried out during the period from January to December 1999. Pneumonic lungs were attempted bactenological findings and antibiotic susceptibilities. The results obtained were as follows; 1. Of 158 slaughtered pigs, 97(61.4%) pigs had pneumonic lesions in the lung, and the prevalence was high in winter, spring, autumn, and summer in order. f. The bacteria isolated from pneumonic lesions were pasteurella spp, 13 heads(34.2%), streptococcus spp, 6(IS.8%), actinobacillus spp, 3(7.9%), coliform 4(10.5%) and the other bacteria, 12(31.6%). 3. These isolates were highly susceptible to the antibiotics of enrofloxacin 30(78.9%), cephalothin 23(73.6%) and ceftiofur 27(71 %). 4. Histopathologically, swine enzootic pneumonia and pleuropneumonia lesions were observed. The swine enzootic pneumonia lesions were consisted of peribronchiolar lymphoid hyperplasia and exudate in alveolar lumen. The pleuropneumonia lesions were consisted of thrombosis, alveolar wall thickened by mononuclear cells and neutrophil deposition.