Redox reactions are central to all life. It is therefore unsurprising that organisms have evolved numerous strategies to monitor and respond to different cellular redox species. Central to these processes are redox-regulated proteins, which respond to specific redox species via oxidative post-translational modification of defined cysteine residues (thiol oxidation). Protein thiol oxidation is increasingly recognised as an important regulator of many physiological processes whilst aberrant regulation may play a key role in many different pathologies. This EMBO Workshop will bring together researchers employing a broad range of methodologies and model organisms to understand mechanisms and targets of protein thiol oxidation as well the relevance of thiol oxidation for organismal physiology and pathology.