ABSTRACT. We extend a result of Herstein co,cerning a derivation d on a prime ring R satisfying [d(x),d(y)] 0 for all x,y R, to the case of semiprime rings. An extension of this result is proved for a two-sided ideal but is shown to be not true for a one-sided ideal. Some of our recent results dealing with U*-and U**-derivations on a prime ring are extended to semiprime rings. Finally, we obtain a result on semiprime rings for which d(xy) d(yx) for all x,y in some ideal U.