Fabrication and characterization of amorphous carbon nitride a-CNx microelectrodes are reported. These electrodes were prepared by DC-sputtering of a thin carbon layer on sharpened glass tip. The kinetic parameters (k0 and α) and the diffusion coefficient of the ferri-ferrocyanide redox probe were determined by steady-state voltammetry (CV) and by electrochemical impedance spectroscopy (EIS), and were used for characterizing both the electrochemical sensitivity of microelectrodes and their dimensions. The cathodic activation procedure of the electrode resulted in an increase of the electron rate constant. This procedure provides a new way for the fabrication of carbon microelectrodes for local electrochemical measurements.