Effects of Aroclor 1254, on hematological disturbance were investigated in the olive flounder, Paralichthys olivaceus. Flounders were exposed to waterborne PCB (3.0${mu}g ; L^{-1}$) for 00 days. Blood samples were taken to determine their hematological disturbances. Plasma calcium concentration was significantly decreased in PCBs exposed flounder compared to the control group, while magnesium and inorganic phosphorus concentrations in PCBs exposed flounders were not significantly influenced during the test Belied. Although plasma total protein and albumin level were significantly reduced compared to the control group after 40 days, plasma glucose level was found to be significantly increased over the control group. Exposure to waterborne PCBs resulted in significant increase in the various enzyme activities, such as GOT, GPT and ALP in the flounder. The results of the present study led us to conclude that concentration of PCBs 3.0${mu}g ; L^{-1}$ of the estuarine could markedly affect the hems tological distribution of olive flounder, Paralichthys olivaceus.