In recent years fatty acid composition of vegetable oil has become important due to determination of its positive effects on oil quality and health. Fatty acid composition of oil seed is not always constant and characteristic differences among species exist. In addition to that fatty acid composition varies depending on genetic, ecological, morphological, physiological and cultural factors. Thus, it is important to determine how fatty acid composition changes at which conditions because it effects oil quality. Many scientific studies have been done to alter fatty acid composition. It was determined that particularly increase of oleic acid content has positive effects on shelf and life oxidation stability of oil, and health (heart, vascular diseases and cancer). In this review it had been focused on the studies to increase oleic acid level in vegetable oil, its effects on quality of vegetable oil and its usage areas in food industry.