The distributions of sanitary indicative bacteria and pathogenic bacteria in seawater and four species of farmed fishes, including oliver flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major) and sea bass (Lateolabrax japonicus), collected at fish farms located in the southern coastal area of Korea were investigated from May to October in 2004. The detection rates of fecal coliform and Entirococcus spp. of sanitary indicative bacteria in all samples were $38.9\%$ and $23.8\%$, respectively. The occurrence of fecal coliform was highest of $58.3\%$ in Busan, Geoje and Wando area, followed Yeosu $33.3\%$, Jeju $12.5\%$, Tongyeong $11.1\%$. The occurrence of Enterococcus spp. was highest In Wando area ($45.8\%$), followed by Yeosu ($33.3\%$), Tongyeong ($22.2\%$), Busan ($16.7\%$), Geoje and Jeju ($12.5\%$). The detection rate of fecal coliform was higher than that of Enterococcus spp., except in the Tongyeong area. There was no difference in the detection rate of fecal coliform from May to October, but the detection rate of Enterococcus spp. increased with seasonal warming seawater temperature. Among the pathogenic bacteria, the detection rate of Vibrio alginolyticus ($49.2\%$) in all samples was highest, followed by V. parahaemolyticus ($36.5\%$), Staphylococcus aureus ($6.3\%$), Salmonella sp. ($2.4\%$). However, V cholerae, V. vulnificus and Shigella sp. were not detected in all tested samples. The detection rates of V. parahaemolyticus and V. alginolyticus increased with seasonal warming seawater temperature from May to August.