An ester-modified silicone derivative of formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are the same or different and each represents a saturated or unsaturated straight- or branched-chain aliphatic hydrocarbon group having from 2 to 30 carbon atoms, a saturated or unsaturated alicyclic hydrocarbon group having from 3 to 30 carbon atoms or an aromatic hydrocarbon group having from 6 to 30 carbon atoms; l and m each represents a number of 0 to 100; n represents a number of 1 to 100; a represents a number of 3 to 16; and b represents a number of 1 to 3 is disclosed as well as a cosmetic composition containing the ester-modified silicone derivative.