The present invention relates to a cosmetic composition for keratin fibers, including: at least one fatty material including (i) at least one plant oil formed by at least one triglyceride derived from fatty acids, and/or (ii) at least one liquid fatty acid ester other than triglyceride； and at least one oxidizing agent, wherein a) 50% by weight or more, relative to the total weight of the fatty acids in the triglyceride(s), of the fatty acids in the triglyceride(s) have 18 or more carbon atoms and at least one carbon-carbon double bond, b) the fatty acid in the liquid fatty acid ester other than triglyceride has 16 or more carbon atoms and/or at least one carbon-carbon double bond, c) the pH ofthe composition is less than 8. The present invention can provide keratin fibers with superior cosmetic properties or perm performance, can reduce the damages to the keratin fibers, and can improve the feel to touch of the keratin fibers.
