Poly(ferrocenylsilane) (PFS), composed of electroactive ferrocene units existing in the polymer main chain, was directly dropped on the DNA modified glassy carbon electrode (GCE). The electrochemical and electrocatalytic behaviors of PFS/DNA/GCE were investigated in detail. Cyclic voltammograms of the PFS/DNA/GCE showed two pairs of reversible redox peaks, indicating a stepwise oxidation of the electroactive units. It was found that DNA film played a key role in immobilizing the PFS and facilitating the electron transfer between electroactive units of PFS and the GCE surface. Moreover, the PFS/DNA/GCE showed a good electrocatalytic ability to the oxidization of ascorbic acid (AA), suggesting it had the potential application as a new type of sensor to detect AA. (C) 2008 Published by Elsevier B.V.