Abstract. Let I ⊂ J be monomial ideals of a polynomial algebra S over a field. Then the Stanley depth of J/I is smaller or equal with the Stanley depth of √ J/ √ I. We give also an upper bound for the Stanley depth of the intersection of two primary monomial ideals Q, Q ′ , which is reached if Q, Q ′ are irreducible, ht(Q + Q ′ ) is odd and √ Q, √ Q ′ have no common variable.