Over the past two decades, the deoxygenation (i.e. the reduction of the sulfinyl group) of free sulfoxides, R 2 S=O, has been extensively studied and described in a number of reviews. However, the deoxygenation of coordinated sulfoxide ligands and metal-ion mediated deoxygenation of sulfoxides has received much less attention and no general overview of these processes has been presented. Correcting that omission is the major goal of this review. Although details of syntheses that involve the deoxygenation of sulfoxide ligands are presented, particular emphasis is placed on discussion of both the common features and differences in the reactions of S- and O-bonded sulfoxides. Along with general consideration of experimental results, an attempt is made to show that most of the methods for the reduction of the very strong S--O bond in S-coordinated R 2 SO ligands are based on an initial activation of the sulfinyl oxygen by a reagent having a highly reactive electrophilic center. In contrast, in the case of O-bound sulfoxides, the metal ion itself plays the role of the electrophilic reagent and thus promotes the deoxygenation reaction. In order to provide a clearer picture of sulfoxide deoxygenation reactions, possible reaction pathways are discussed and evidence for these mechanisms is provided.