Hypercholestermia is the most common pathologic process underlying atherosclerosis and cardiovascular diseases. Alpha-linolenic acid (ALA, 18:3, omega-3) is believed to protect the cardiovascular system. This study was carried out to investigate the protective effect of linseed, soybean, or walnut oils as omega-3 rich oils in rats compared to control diet. Furthermore, the therapeutic effect of linseed, soybean and walnut rich diets on lipid profile and liver functions of rats after feeding high fat diet. This study also was carried out to evaluate the hepatic bioconversion of alpha-linolenic acid (ALA, 18:3, omega-3) to eicosapentaenoic acid (EPA, 20:5, omega-3) and docosahexaenoic acid (DHA, 22:6, omega-3) in rats fed on diets rich with oils from linseed, soybean and walnut. The physical and chemical properties as well as the content of fatty acids and sterols of linseed, soybean and walnut oils were studied. Two biological experiments were carried out to investigate the aims of such study.The obtained results showed that the overall beneficial effects provided by high level of ALA were better than those given by low levels of ALA. Linseed oil exerted a hypolipidemic effect and could be considered as a promising functional food in cardiovascular disease and as an alternative source of omega-3 PUFAs that could provide important benefits to our cardiovascular health.