It has been accepted that the most reliable method to prepare chemically modified carbon electrodes is introduction of carboxyl groups on carbon surfaces by oxidative treatment, such as heating in air, treatment in a radio-frequency O₂ plasma, anodization in an aqueous solution or chemical oxidation, followed by chemical formation of amide bonds between the active functional groups and amino compounds. However, carbon electrodes derivatized based on these oxidative treatments exhibit markedly high background currents in electrochemical measurements, which prevents analytical application of the modified electrodes. For this decade, it has been demonstrated that organic molecules can be introduced on carbon surfaces via covalent bonding with no or less problem of high background currents by taking full advantage of the chemical properties of sp² hybridized carbon as an electrode material as follows: cathodic reduction of aromatic diazonium salts; anodic oxidation of amino compounds; anodic oxidation of arylacetic acids; anodization in 1- alkanols. This review provides a comprehensive overview of these methods as a useful tool for preparation of chemically modified carbon electrodes. Some analytical applications of modified electrodes obtained by these electrochemical methods are also compiled.