Copper indium disulphide, CuInS2 thin films were successfully prepared by electrodeposition without usual heat treatment in H2S atmosphere. Thin films were deposited from acidic aqueous solution containing CuSO4, In-2(SO4)(3) and Na2S2O3 at -0.9 V vs. Ag/AgCl for 300-1200 s. Single phase CuInS2 films were obtained at pH about 1.5 by the correct adjustment of the Cu2+/In3+ ratio, with the concentration of Na2S2O3 fixed at 400 mM. Well-crystallized films were obtained by annealing in vacuum at 673 K. From EDX analysis, it was found that the compound CuInS2 did not always exist in exact stoichiometry of Cu:In:S = 1:1:2. The conduction type of the film changed from p to n in the indium-rich region. This result suggests the possibility of controlling the properties of thin films by varying the concentration of each chemical in the initial electrolytic solution.