Lipids are important molecules that serve as a source of energy and are critical components of the physical and functional structure of cells Linoleic acid (C18:2, n-6) and a-linolenic acid (C18:3, n-3) are classed as essential fatty acids (EFA) in mammals. Omega-3 polyunsaturated fatty acids (n-3) have a number of positive effects on human and animal health. In particular, the ratio of omega-6 polyunsaturated fatty acids (n-6) to n-3 may play an important role in several aspects of animal health, production and reproduction. The aim of this study was to Investigation of the effects of n-3 or n-6 fatty acids on blood cholesterol and triglyceride in ewe. Ten ewe (48.94±11.44) non preganant were randomly allotted to two groups. The animals were fed diets containing; 70 mL/ewe canola oil (omega 3 source) and 70 mL/ewe sunflower oil (omega 6 source). The experiment was conducted as completely randomized design. Serum metabolite measurements obtained from blood samples collected during days 0 and 42 were analyzed using the MIXED procedure of SAS 9.1. Serum triglyceride concentrations were higher (P < 0.05) in ewes fed oil sunflower (24.10±1.30 versus 15.80±1.30 mg/dl). Serum cholesterol was not affected by use of polyunsaturated fatty acids n-3 and n-6 in the diet.