We report on the biosorption of copper ions in dried leaves from the Brazilian flora. By Electron Paramagnetic Resonance (EPR) it is shown that the copper ions are incorporated in the leaves in a strongly axial site. Washing with an acidic solution does not remove the copper from the leaves, but does modify the axial site symmetry. Infrared absorption seems to be compatible with a site which is located near to a simple or a double carbon — oxygen bond. Dried leaves are a good and commercially interesting alternative for sorption of metal ions compared to other biomasses.