ABSTRACT. The following theorem is proved: Let r r(y) > 1, s, and be non-negative integers. If R is a left s-unital ring satisfies the polynomial identity [xy x'y"x t, x] 0 for every x, y E R, then R is commutative. The commutativity of a right s-unital ring satisfying the polynomial identity [x/-yrxt, X] 0 for all x, y E R, is also proved.