8-Hydroxy-2'-deoxyguanosine (8-OHdG) detection by high performance liquid chromatography (HPLC) with amperometric detection was studied using a Au electrode modified with different dendrimer based thin films. Gold electrode is thiol-modified, forming self-assembled monolayers on which different generation PAMAM dendrimers with terminal functional groups ÀCOOH and ÀNH 2 have been attached using peptidic bonds. Results obtained in synthetic samples show low limits of detection and quantification for 8-OHdG (1.2 Â 10 À9 and 3.7 Â 10 À9 M respectively), with matrix interference elimination, thus avoiding sample pretreatment. Best results are obtained with electrodes modified with aliphatic amino thiols and 3.5 and 4.5 generation carboxylated dendrimers (Au/AET/DG 3.5 and Au/AET/DG 4.5 ), demonstrating that these materials constitute a good alternative for 8-OHdG determination in biological fluids.