PROBLEM TO BE SOLVED: To provide a polyvalent unsaturated fatty acid-containing oil and fat composition in which occurrence of a return odor of polyvalent unsaturated fatty acid-containing oil and fat is suppressed for a long time, to provide an emulsion composition or powder composition of the polyvalent unsaturated fatty acid-containing oil and fat composition, to provide food and drink products, a pharmaceutical composition or a cosmetic each of which contains the emulsion composition or powder composition, and to provide a method for reducing the return odor of the polyvalent unsaturated fatty acid-containing oil and fat.SOLUTION: The polyvalent unsaturated fatty acid-containing oil and fat composition contains: the oil and fat containing polyvalent unsaturated fatty acid having 18 or more carbon atoms and 2 or more double bonds basic amino acid and/or basic peptide and an emulsifier.
