To reduce an economic loss by swine disease, this study was designed to provide helpful data which are particularly useful for each individual farm. From february to December 2009, a total of 18,173 slaughter pigs (612 herds) were randomly sampled, which were produced just in southern region of Gyeonggi-do. We examined all of them for the slaughter lesions of 8 kind diseases such as swine enzootic pneumonia (SEP), pleuritis (PL), pleuropneumonia (PP), white milk spot in liver (WMS), papular dermitis (PD), pericarditis (PC), ileitis (IL) and peritonitis (PT). Twenty four percentages (4431/18173 pigs) of the examined pigs had no lesions about 8 kind diseases. Among the pigs with lesions, the numbers of the pigs with just one lesion were 7,637(42%), followed by 4,551(25%) pigs with 2 lesions. Average prevalence of pigs were 56.5% (10288/18173 pigs) in SEP, followed by 34% in PL, 12.4% in PP, 10.1% in WMS, 6.1% in PD, 4.7% in PC, 0.1% in IL and PT, respectively. Each prevalence of SEP, PL, PP and PD was higher in spring than in winter, respectively (P<0.01). Among the pigs (n=6,105) with 2 or more than 2 kinds of lesions the top (55.5%) was the pigs with SEP and PL, and the second was 1,179 (19.3%). Swine enzootic pneumonia was considered as one of the more likely risk factors for initiation or/and acceleration of other diseases such as PL, PP, WMS and PD. The lesion of SEP was relatively severe since the pigs with late stage were more (7,277 pigs) than those with early stage.