The simultaneous identification and quantitative measurement of the production levels of thousands of different proteins in a biological specimen remains an unachieved goal of modern proteomic research. Advances in the development of microarray-based platforms for highly parallel detection of proteins have therefore received a considerable impulse during the last few years. Here, we review the existing reagents for affinity capture of protein targets, as well as the techniques used for their immobilization on solid supports and methods for the detection of binding events, underlining the problems and the opportunities in this continuously evolving research field.