All the proteins synthesized in a cell undergo several post-translational modifications that are essential in their functional regulation. Among these, the change of the redox state of Cysteine residues is assuming a great interest: this modification in fact, represents a very dynamic and regulated balance. There are several reversible oxidative events that can occur and that are difficult to detect. In this work we describe a methodology useful to recognize and to select Cysteines containing proteins on the basis of their redox state. The strategy is based on the selective labeling of the interested proteins and allows their visualization by Western Blot, enrichment by affinity chromatography and finally the identification of the protein and of the modified Cysteine residues by mass spectrometry. This methodology can be used in proteomic studies to recognize redox-sensitive Cysteine containing proteins and nitric oxide targets.