MetaNetX.org allows to access, analyse and manipulate genome-scale metabolic networks as well as biochemical pathways. It consistently integrates data from various public resources and makes the data accessible in a standardized format using a common namespace. Models can be interactively compared, analysed (e.g. detection of dead-end metabolites/reactions, flux balance analysis or simulation of reaction/gene knockouts), manipulated and exported. Users can upload their own metabolic models.