B Fadaee - Department of Mathematics,Faculty of Science, University of Kurdistan, Sanandej, Iran
E Ghaderi - Department of Mathematics, Faculty of Science, University of Kurdistan, Sanandej, Iran
S Naseri - Department of Mathematics, Faculty of Science, University of Kurdistan, Sanandej, Iran

Let A be a C*-algebra, and let δ, τ : A → A** be a continuous linear map. We assume that δ, τ acts like a generalized derivation at orthogonal elements for several types of orthogonality conditions such as ab = ۰, ab*= ۰, and a*b = ۰. In each case, we characterize the precise form of δ and τ.

Derivaton, Generalized derivation, Orthogonal elements, C*-algebra