Let S be a foundation locally compact topological semigroup, and let Ma(S) be the space of all measures μ ∈ M (S) for which the maps x → |μ| * δx and x → |μ| * δx from S into M (S) are weakly continuous. The purpose of this article is to develop a notion of character amenability for semigroup algebras. The main results concern the χ-amenability of Ma(S). We give necessary and sufficient conditions for the existence of a left χ-mean on Ma(S) * .