Abstract: Hyperlipidemia refers to increase of triglyceride (TG) and/or total cholesterol (T-cho) in blood. Fatty Acids (FAs) have important roles in the lipid metabolism. The aim of this study was to determine the FA composition of plasma lipid fractions in dogs with hyperlipidemia and to evaluate the FA composition as a new diagnostic marker for obesity at early stage. Thirty-nine dogs were classified into healthy or hyperlipidemia based on the criteria to diagnose hyperlipidemia. The blood biochemical values, such as TG, T-cho, glucose, insulin, adiponectin and Non-Esterified Fatty Acid (NEFA) were measured. FA composition profile was performed on GC/MS system. The values of plasma TG, insulin and NEFA of the hyperlipidemia group were significantly higher than that of control group. Hyperlipidemia group tended to show lower concentration of adiponectin. It was found that only the levels of TG and NEFA, but not T-cho increased significantly in early stage of hyperlipidemia. In hyperlipidemia group, percentages of myristic acid (C14:0), parmitoleic acid (C16:1) and oleic acid (C18:1) increased in total FAs. And the percentage of C18:1 increased in NEFA. Indeed, the higher level of insulin and lower adiponectin concentration were seen in hyperlipidemia group. These results suggest that appearance of insulin resistance may be the result of increases of certain FAs in early stage of insulin resistance.