Metal nanoparticles has gained increasing attention due to its wide range of applications. The properties can be fine tuned by controlling the size and shape of the nanoparticles. Despite various preparation methods available, electrochemical synthesis offers a viable alternative since they are versatile, easy to prepare and does not require laborious experimental conditions. Moreover the nanoparticles adhers to the surface of the electrode and hence can be employed without any pre-treatment procedures. The present book provides a comprehensive view on the preparation of metal nanoparticle (especially Ag, Co, Sn and Pd) with suitable size and shape using electrodeposition technique. The application of the electrodeposited metal nanoparticle in sensors and fuel cells (oxygen reduction reaction) are discussed.