Chronoamperometry was used to investigate the initial non-stationary stages during the electrocrystallisation of silver thiosulphate complexes on a polycrystalline silver rotating disc electrode. At the beginning of the experiment a large current peak was always observed, followed by a current decrease after several seconds. A new electrochemical reaction model was introduced, suggesting the formation of 2D silver clusters as a reaction step which precedes the actual moment of 3D nucleation. By doing so, the nucleation phenomena observed during the so called induction period do not have to be considered as being a stochastic process consuming no current, as is often done in the literature. The short time transients are simulated using a numerical computational method, solving the basic mass transport equations with the boundary conditions as a function of the newly proposed model. Satisfying fitting results are obtained, thus allowing one to deduce values for the different electrochemical parameters involved.