Gold(III) complexes constitute a new class of metallodrugs, of potential interest for cancer treatment. During the past decade different kinds of gold(III) complexes have been reported to be appreciably stable under physiological-like conditions and to manifest relevant antiproliferative properties against selected human tumor cell lines. Some relevant examples are presented. Recent investigations point out that the interactions of cytotoxic gold(III) complexes with DNA are significantly different and weaker than those of platinum analogues; important interactions with model proteins and target proteins have been reported as well. Accordingly, the mechanisms of action of cytotoxic gold(III) complexes seem to be innovative and substantially different from that of cisplatin. Relevant antimitochondrial effects were demonstrated in some cases, eventually leading to cell apoptosis.