One of the major tasks to be accomplished in the postgenomic era is the characterization of PTMs in proteins. The S-nitrosation of protein thiols is a redox-based PTM that modulating enzymatic activity, subcellular localization, complex formation, and degradation of proteins, largely contributes to the complexity of cellular proteomes. Although the detection of S-nitrosated proteins is problematical due to the lability of S-nitrosothiols, with the improvement of molecular tools an increasing range of proteins has been shown to undergo S-nitrosation. We here review recent proteomic approaches for the systematic assessment of potential targets for protein S-nitrosation. The development of new analytical methods and strategies over the past several years now allows us to investigate the nitrosoproteome on a global scale.