The heat of swelling of green tea with water was measured. The heat of swelling decreased exponentially with increasing water content and assumed negative values at >0.08gg(-1) of water content. The dissolution of green tea extracts was endothermic and the swelling of tea ghost (tea grounds) was exothermic. When the curves for dependence of water content on the heat of swelling of tea ghost and that for the heat of dissolution of tea extract are combined, the synthesized curve agreed quite closely with the curve for the heat of swelling of tea. We thus conclude that the heat of swelling of tea is the sum of the heat of swelling of hydration of the insoluble materials and the heat of dissolution of soluble components of tea.