Detailed and comprehensive characterization of proteins is a major goal of proteomics. This goal has become more realistic today with the latest high-resolution mass spectrometers capable of faster sequencing in a high-throughput fashion and with the emergence of new techniques such as protein and peptide microarrays. A promising area for discovery is the application of these advanced mass spectrometric and other quantitative proteomic methodologies to laboratory diagnosis. This review focuses on the role of proteomics in the development of new laboratory diagnostics and the implications for routine diagnosis and monitoring of diseases.