Abstract. We study a filtration on the group of homotopy classes of self maps of a compact Lie group associated with homotopy groups. We determine these filtrations of SU (3) and Sp(2) completely. We introduce two natural invariants lz p (X) and sz p (X) defined by the filtration, where p is a prime number, and compute the invariants for simple Lie groups in the cases where Lie groups are p-regular or quasi p-regular. We apply our results to the groups of self homotopy equivalences.