Abstract: The current invention refers to the procedure to obtain compositions rich in omega 3 fatty acids with content in phytanic acid below 90 ?g per gram of oil. The current invention also refers to the obtaining of compositions rich in DHA with a content in phytanic acid below 90 ?g per gram of oil, more specifically between 650-950 mg/g, that is, between 65% and 95% of DHA in weight and values of PhA below 90 ?g, preferably below 5 ?g per gram of the oil forming the composition. The compositions obtained are used in the field of food supplements, nutritional products and pharmaceutical products due to their prophylactic action and therapeutic effect.