All electrochemical sensing techniques are based on electrochemical processes that occur at the electrode surface. Therefore, electrode surface modification plays a crucial role in electrochemical sensor development. Popular electrode surface modification techniques include physisorption, covalent modification and homogeneous multilayer thin film formation etc. The surface modified electrodes are termed as chemically modified electrodes (CMEs). CMEs exhibit, better over redox potentials, fast electron transfer kinetics, good electro-optical properties, and stable electrode surfaces in electro analysis. The present chapter summarizes the advantages, and disadvantages of various types of electrode modification techniques, characterizations of the modified electrode surface and applications in the field of electroanalysis.