Abstract: Organopolysiloxanes composed of an organopolysiloxane segment and a poly(N-acylalkyleneimine) segment which is bonded to at least one silicone atom of said organopolysiloxane segment via an alkylene group containing heteroatom(s) and which consists of repeating units represented by formula (1): ##STR1## wherein R.sup.1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; and n is a number of 2 or 3;wherein the weight ratio of the organopolysiloxane segment (a) to the poly(N-acylalkyleneimine) segment (b) [(a)/(b)] is at least 5/95 and less than 40/60, and the weight-average molecular weight is from 10,000 to 500,000.These organopolysiloxanes are soluble or dispersible in water and can form a film with an excellent texture. Thus, they can be appropriately employed as additives for cosmetic products.