The emergence of proteomics, the large-scale analysis of proteins, has been inspired by the realization that the final product of a gene is inherently more complex than the gene itself. Shortfalls in the ability of bioinformatics and other related sciences to predict both the existence and function of genes have also illustrated the need for protein analysis. Better than gene sequencing or quantitative amplification, proteomics tools allow the study of disease phenotype by the detection and quantification of single protein in body fluids. Moreover, only through the study of proteins can posttranslational modifications be determined, which can profoundly affect protein function. Proteomics has been enabled by the accumulation of both DNA and protein sequence databases, improvements in mass spectrometry and the development of computer algorithms for database searching. In this review, it has been described why proteomics is important, how it is conducted, and how it can be applied to various spheres of pharmaceuticals and health sciences. It has been concluded that currently the most practical application of proteomics is the analysis of target proteins as opposed to entire proteomes