For the recent years, considerable efforts have been made to rationalize the techniques of research and monitoring of biological effects of marine pollutants such as heavy metals, polychlorinate biphenyls (PCBs), organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), organophosphorus pesticides. This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by the changes in lipid components of the flounder (Paralichthys olivaceus) in Yellow Sea of Korea. Hemoglobin levels in serum of cultured and wild flounders in Yellow Sea were significantly lower (5−15% and 20−25%, respectively) than those of wild flounder in Pohang. Triglyceride (TG) contents in serum of cultured flounders in Yellow Sea were 10−40% higher than those of wild flounder in Pohang. Total and low density lipoprotein (LDL)-cholesterol contents in serum of flounders in Yellow Sea were significantly 10−15% and 30−35% (cultured), and 10−20% and 20−25% (wild), respectively, higher than those of wild flounder in Pohang. Atherogenic index (AI) and T-Chol/PL ratios in serum of cultured and wild flounders in Yellow Sea were significantly 20−45% and 10−15%, 6−35% and 15−35%, respectively, higher than those of wild flounder in Pohang. These results suggest that near-coastal waters as well as neritic waters of the Yellow Sea might be affected by pollutant input.