Three quaternary sulfides ACuFeS(2) (A = K, Rb, Cs) with the ThCr2Si2-type structure were prepared from alkali metal carbonate A(2)CO(3), Fe2O3, and CuO by CS2/N-2 sulfurization. All of the samples show semiconducting behavior. Magnetic susceptibility data indicate the presence of localized moment arising from the di- and trivalent iron ions. The semiconducting properties observed in this system are in contrast to the metallic behavior predicted by theoretical calculations.