Let R be a commutative ring with nonzero unity and S a multiplicatively closed subset (m.c.s) of R. An S-disjoint ideal of R is called zS-ideal if there exists s = sI ϵ S and whenever MS(a) ⸦ MS(b) for some a ϵ I and b ϵ R, then sb ϵ I, where MS(a) = {MaxS(R) : sa ϵ M for some s ϵ S}, for each a ϵ R. In the present paper, we introduce and study the concept of zS-ideal which is an extension of the notion of the z-ideals. We generalize some well-known results on z-ideal to zS-ideal. In addition, many examples, characterizations, and properties of zS-ideal are given. We also investigate the relation between z-ideals and zS-ideals of a commutative ring.