Viable, non-dormant seeds will germinate in the presence of sufficient oxygen once a certain level of hydration is reached. The rate of uptake of moisture is critical in determining the period between the start of hydration and the initiation of germination. The increase in moisture content of wheat seed set to germinate on filter paper with excess water was measured, at intervals during incubation at temperatures ranging from 12°C to 30°C, for seeds of 25 to 50% initial moisture content (dry basis), until all seeds had germinated. The rate of uptake of moisture is described using a liquid diffusion model where the maximum moisture content attained at germination replaces the equilibrium or saturation moisture content used in similar absorption models. The maximum moisture content attained at germination is defined as the average of the mean seed moisture content immediately before germination (i.e. no seeds germinated) and the mean moisture content after the majority of seeds (> 90%) have germinated, where germination is defined as appearance of at least 1 mm of radicle. The model predicts the observed seed moisture content equally well for seeds from low to high initial moisture content. The diffusion coefficient was best described by an Arrhenius temperature function and was found to be almost twice as high as the values found in previous studies of water absorption by non-germinating seeds.