The behaviour of the diffusion equation that results from assuming the boundary condition C(0,t) = C-b exp(-bt), with C-b (bulk concentration) and b constant, was examined. This condition reflects the behaviour of the diffusion around isolated nuclei growing onto a substrate. The diffusion equation under this boundary condition was solved and compared the results with the current transients obtained during electrodeposition. An expression for the fractional surface area of the deposit, S(t) and other parameters are obtained. The system reproduces the electrodeposition current transients in the chosen Cu2+/Cu couple and gives the values of the measured parameters at least within one order of magnitude. Some discrepancies between the theory and experimental results are examined and possible causes are suggested. (C) 2003 Elsevier Science B.V. All rights reserved.