The progress of genomic technologies enables systematic analysis of biological samples at the molecular level. Although these techniques provide important insights into the living process, all the data regarding DNA sequence variations or RNA transcript levels of cells will only provide a partial picture. It can be expected that in many if not the majority of disease cases proteomics are necessary to complete the picture. This holds especially true for the diagnosis of complex diseases and improved risk stratifications, and biomarkers with high sensitivity and specificity are the key. Biomarkers are a class of biological molecules with characteristic features which can be measured and visualized. They have an outstanding role in the identification of normal and diseased states. Moreover, they can give informations whether a disease is just occurring or in progression, and, thus are parameters for diagnostics, prognosis and in the assessment of sequential events.