Let M be a semiprime Γ-ring with involution satisfying the condition that aαbβc = aβbαc (a, b, c ∈ M and α, β ∈ Γ). An additive mapping d : M → M is called Γ * -derivation if d(xαy) = d(x)αy * + xαd(y). In this paper we will prove that if d is Γ * -derivation of a semiprime Γ-ring with involution which is either an endomorphism or anti-endomorphism, then d=0.