Sunflower oil is a high-quality vegetable oil due to its high content of unsaturated fatty acids (approximately 89%). Among unsaturated fatty acids, linoleic acid (omega-6 group oil) is dominant in sunflower oil followed by oleic acid (omega-9 group oil), which are classified as polyunsaturated (PUFA) and monounsaturated fatty acids (MUFA),respectively. The oil being rich in MUFA, low in PUFA and free of trans fatty acids provide a high level of oxidative stability, making it tolerant to high cooking temperatures which is required for food preparation and industrial applications. High oleic sunflower oils are classified as having MUFA levels of 80% and above. The development of sunflower types with high oleic acid and low linoleic acid content is possible through breeding programs. Recently, breeding programs in Thailand have been started to generate sunflower lines with high oleic acid content. The success of the program depends on many factors, especially the effectiveness of the seed screening method.