Protein microarrays are ideal multi parameter platforms for parallel detection and functional characterization of proteins. Since proteins have many different properties, subsets are used in multiplex assays. The new developed HSP-Microarray carries full-length functional and active ligand-binding heat shock proteins (HSP) on nitrocellulose coated glass slides under native conditions. HSP Arrays are indispensable tools to test target-oriented protein-protein and protein-ligand interactions.