With the completion of the human genome sequence, it is now possible to analyze the many individual components that comprise complex biologic systems. Despite this sequence data, understanding the biologic relationships of all proteins of a given cell or biologic sample (the proteome) is still an exceedingly difficult task. However, new technology developments mean that proteomics research can be used to investigate a variety of biologic systems. Already, these studies have given valuable insight for the development of improved diagnostic and therapeutic products. The present review aims to provide a basic understanding of proteomics research by discussing the methods used to study large numbers of proteins and by reviewing the application of proteomics methods to transfusion medicine.