ABSTRACT.    Plankton*Net (http://planktonnet.sb-roscoff.fr) is an open-access iconographic and taxonomic on-line database devoted to marine plankton taxonomy based on Micro*scope (http://starcentral.mbl.edu/microscope/portal.php), a web site initially developed by D. J. Patterson (Marine Biological Laboratory, Woods Hole, USA). The objectives of Plankton*Net are to collate all available taxonomic information on marine plankton, to archive large collections of images, descriptions, references, and observations that would otherwise disappear (e.g. from retiring scientists), to serve special purpose projects (e.g. Harmful Algal Blooms), to provide new taxonomic tools (electronic keys) and to create a European network of plankton taxonomy specialists. Three nodes have been set up (Bremerhaven, Roscoff and Lisbon) and two others will join soon (Sweden, Lake Kinneret). Each node contains collections of images which can be easily uploaded by registered users. Images are linked to taxonomic databases from a central server (Cu*Star for species names, Biopedia for species description). This allows to instantly connect a given image to images from the same taxon available in other collections and to navigate through taxonomy. At present, nodes are independent, but soon they should soon communicate through XML based protocols. Today, Plankton*Net@Roscoff provides access to about 1,400 images that are freely available for science or teaching under a Creative Commons licence. The pilot phase of Plankton*Net constitutes a European project regrouping four partners coordinated by A. Kraberg from the Alfred Wegener Institute (Bremerhaven) and funded by the EU (Research Infrastructure - 026071).