The domain specific nature of biosignal storage formats, along with the lack of support for metadata in generalpurpose biosignal libraries, has hampered the easy interchange of biosignals between disciplines and their integration with physiological modelling software. Extensible Biosignal Metadata (XBM) is introduced as a standard framework to facilitate the sharing of information between and within research groups for both experimentalists and modellers; to help establish more web-accessible biosignal repositories; and, by using semantic web technologies, to result in the discovery of knowledge by automated reasoning systems.