A stable and accurate finite difference algorithm and the use of oblate spheroidal coordinates enables the reduction of the number of spatial and temporal grid points necessary to solve the diffusion equation for a microdisc electrode for linear sweep and chronoamperometric conditions. The application of second and fourth order discretisation of the spatial derivatives of the diffusion equation is compared. The latter is more accurate and efficient for simulations to longer times, while the former is more efficient when one-dimensional diffusion is predominant. (C) 2003 Elsevier B.V. All rights reserved.