In the present study, the surface of pencil graphite electrode (PGE) was modified using succinamic acid functionalized second generation poly (amidoamine) (PAMAM) dendrimer (G2-PS) to design a novel single-use electrochemical DNA biosensor. The microscopic characterization of G2-PS/PGE5 was performed by using scanning electron microscopy (SEM). The effects of the experimental parameters, such as dendrimer concentration, activation of PGE surface, DNA concentration, and different labelling of DNA using chemical groups were explored upon to the electrode response by using different electrochemical techniques; differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). After immobilization of calf thymus double stranded DNA (ctDNA), or short DNA oligonucleotide (DNA ODN) onto the surface of dendrimer modified electrode, an enhanced sensor response was recorded using G2-PS/PGE5 in contrast to one of unmodified PGEs. The features of dendrimer modified DNA biosensor were comprehensively discussed in comparison to earlier reports. (C) 2014 Elsevier B.V. All rights reserved.