The effect of lipid oxidation on the taste and flavor of dashi-jiru (broth) from niboshi (boiled and dried sardine) was determined. Lipid was extracted from several kinds of commercially available niboshi. The amount of lipid was about 4.3% in the body, this being greater than the value in the Standard Table of Food Composition in Japan (4 th revised edition), while the lipid content of the head was 1.3-2.2 times that of the body. Both the carbonyl value (COV) and thiobarbituric acid reactive substances (TBARS) value were high, showing that the lipid in niboshi was fairly well oxidized. The fatty acid composition of niboshi was changedby lipid oxidation, the content of such polyunsaturated fatty acids as icosapentaenoic acid and docosahexaenoic acid, which are rich in the fish, particularly being decreased. The taste and flavor of dashi-jiru from niboshi were correlated with the degree of lipid oxidation, a higher level of oxidation leading to a more fishy flavor and unacceptable taste.