The TINNET COST Action is a unique effort and the only international network world-wide focusing on subtyping of tinnitus, the identification of the neuronal correlates of these subtypes and their molecular genetics. The heterogeneity of tinnitus is the major reason for inconsistent results in tinnitus studies, both in neuroimaging studies and clinical trials, and represents the major barrier in the development of innovative and more efficient treatments for tinnitus. This barrier will be addressed by this COST Action which will identify clinical criteria for pathophysiologically distinct subtypes of tinnitus. The Action will further improve the understanding of the pathophysiological mechanisms of the different forms of tinnitus and provide crucial information for the development of innovative hypothesis driven treatment approaches. Thus the Action has high potential impact on many different levels.