Moisture migration IS common problem in many composite food systems where compartments of high/low water activity are adjacent. Water diffuses from the high into the low water activity compartment leading to irreversible texture loss. Moisture distribution in a model multi-compartment food (agar gel/sponge-cake) was experimentally evaluated at 20degreesC by measuring moisture content profiles as a function of time. A mathematical model was developed to simulate moisture transport within agar gel and sponge-cake. The transport and equilibrium properties of water for each compartment (water diffusivity and sorption isotherm) are important factors required for calculations and modelling. They were evaluated using an independent water vapour sorption experiment. Moisture diffusivity within sponge-cake (similar to1 x 10(-10) to 1 x 10(-9) m(2) s(-1)) was rate-limiting for moisture transport and varied with moisture content. This behaviour may be related to the decrease of sponge-cake porosity with moisture content increase. The model was then validated with various initial a(w) for agar gel.