This review article summarizes the development in bioinorganic chemistry of vanadocene dichloride and its derivatives. It is focused mainly on studies related with biological activity appearing in past four decades, after the antitumor activity of bent metallocenes was discovered by Petra Kopf-Maier and Hartmut Kopf. The first part deals with the unique hydrolytic chemistry of vanadocene dichloride and the reactivity with biologically relevant molecules, necessary for understanding of its antitumor effect on the molecular level. The second part summarizes the results of in vitro and in vivo biological assays. It covers not only the experiments related with antitumor activity but also a series of studies focused on the spermicidal properties with unique mechanism of action. A special attention is given to structure–activity studies on modified vanadocene compounds.