Abstract: The invention concerns Au(III) complexes of the type [AuIIIX2(Pdtc)] (X=halogen, pseudo-halogen; pdtc=peptide-/esterified peptidedithiocarbamato) which are able to both maintain the antitumor properties and the lack of nephrotoxic side-effects of the previously reported Au(III)-dithiocarbamato complexes, together with an improved bioavailability through the peptide-mediated cellular internalization. The Au(III) complexes described have shown a significant biological activity on human tumor cell lines and, thus, they can be advantageously used as antineoplastic agents. The preparation method and use for the treatment of tumor pathologies of the Au(III) complexes of the invention are further described.