Various new nucleosides bearing one or two lipophilic groups at the 2′-position have been synthesized. The lipophilic substituents were attached to a 2′-hydroxy, 2′-amino, or 2′-thio function. These lipophilic nucleosidesanchor in large unilamellar POPC vesicles serving as phospholipidmembrane models. The insertion of these molecules into the membranes was investigated by NMR techniques. For comparison