SUMMARYElectrocrystallization of PbO 2 on glassy carbon electrodes was studied in 1 M HNO 3 + 0.1 M Pb(NO 3 ) 2 using cyclic voltammetry, rotating disk electrode, chronoamperometry and scanning electron microscopy. In order to explain the experimental curves a new theory of threedimensional nucleation and progressive growth was developed and applied to analyse the experimental chronoamperometric curves. Numerical approximations led to the determination of kinetic parameters.