A numerical simulation is described for solving the thermal conduction and mass diffusion equations in boards of hardwood timber, and the Einite-volume method used here has been applied to the drying of Eucalypt timber, an Australian hardwood. The predictions of the variation in the average moisture content with time agree well with both ex~erimental data from the literature and analvtical solutions of the-diffusion equation. The nume ical simulation treats the boundary conditions more accurately than the analytical solutions when the moisture movement is two dimensional, as it is through the cross-section of a timber board. This feature makes the simulation useful when describing the drying process under intermittent drying conditions. These conditions are encountered in the drying of timber in solar kilns, and this simulation may be used to predict the distributions of temperature andmoisture content inboards of timber which are being dried intermittently inside conventional kilns. The numerical simulation for intermittent drying has shown, inthe example studied here, chat the same overall change in average moisture concentration can be achieved with 12-hour active drying and 12-hour relaxationperiodaas forcontinuousdryingbyincreasingthedry-bulb temperature by 10°C for this timber. In spite of the higher dry-bulb temperature used in the active drying period of intermittent drying. the moisture concentration profiles within the board are predicted to be more uniform than with continuous drying, because the internal moisture diffusion process continues during the relaxation period. These mare uniform moisture concentration profiles in intermittent drying are likely to result in lower stress levels within the timber than with continuous drying.