Following the age of genomics having sequenced the human genome, interest is shifted towards the function of genes. This new age of proteomics brings about a change of methods to study the properties of gene products on a large scale. Protein separation technologies are now applied to allow high-throughput purification and characterisation of proteins. Two-dimensional-gel electrophoresis (2DE) and mass spectrometry (MS) have become widely used tools in the field of proteomics. At the same time, protein and antibody microarrays have been developed as successor of DNA microarrays to soon allow the proteome-wide screening of protein function in parallel. This review is aimed to introduce this new technology and to highlight its current prospects and limitations.