High Mobility Group Box 1 (HMGB1), a ~25 kDa highly conserved protein, plays key roles in acute sepsis and in chronic inflammatory diseases including diabetes and Alzheimer’s disease. Intracellularly, HMGB1 binds DNA and assists with the regulation of transcription. Extracellularly, HMGB1 is released either by active secretion or by passive release from damaged necrotic cells [1]. It thereby promotes inflammatory responses by numerous mechanisms, including by binding to key pattern recognition receptors such as the Receptor of Advanced Glycation End-products (RAGE) and Toll-Like Receptor 4 (TLR 4). These interactions trigger NF-κB activation, which leads to inflammation.  Thus, control of the HMGB1-receptor interactions represents a promising therapeutic approach for the treatment of a number of inflammatory based diseases [2].  A number of  studies of HMGB1 and it receptors implicate a role for ligand and receptor oligomerisation [3]. In this study, we use surface plasmon resonance to monitor the real time binding of recombinant HMGB1 to DNA, to RAGE and to HMGB1 itself.  HMGB1 is shown to be active by binding DNA and RAGE. HMGB1 is also shown to self associate with high affinity. The role of the self association of HMGB1 and ligand-receptor oligomerisation requires further clarification.