  In the paper we describe derivations of some classes of Leibniz algebras. It
is shown that any derivation of a simple Leibniz algebra can be written as a
combination of three derivations. Two of these ingredients are a Lie algebra
derivations and the third one can be explicitly described. Then we show that
the similar description can found as well as for a subclass of semisimple
Leibniz algebras.
