New experimental approaches are presented which are implemented in rheumatology research. DNA microarray technology and proteome analysis are two new methods which are applied to gain a global survey over the gene expression at the RNA and protein level under various conditions. Based on these methods of molecular medicine important functional proteins in the pathogenesis of rheumatoid arthritis (RA) as well as clinical relevant genetic polymorphisms shall be identified. New insights are expected which will help in the differentiation of clinical entities and in the search for new therapeutic strategies in the treatment of RA.