Nickel-implanted boron-doped diamond electrodes (Ni-DIA) were fabricated in view of their application for carbohydrate detection. This electrode produced well-defined and reproducible voltammograms for 1 mM glucose in alkaline media. The electrode exhibited excellent electrochemical stability with low background current even after ultrasonic treatment, indicating the strong bonding of nickel with carbon. These results indicate the promising use of Ni-DIA for the detection of carbohydrates and amino acids, and thus, an application of ion implantation as the surface modification method is effective for controlling the electrochemical properties of polycrystalline diamond thin films. (C) 2002 The Electrochemical Society.