Quality of fresh tomato fruits is basically determined during growth of the fruits on the plant. Import of water, nutrients and assimilates from other parts of the plant largely determine fruit growth. Previous research has shown that during fruit development 90% of all water entering the fruit is transported via the phloem. Water import via the xylem seems to cease after maximal growth rate of the fruit has be reached. It seems therefore logical to assume that somewhere along the xylem transport path between shoot and fruits a large hydraulic resistance exists, which besides water also restricts Ca 2+ import. Though, previous research has shown that the xylem hydraulic resistance between stem and tomato fruits is not high enough to significantly restrict water flow via the xylem. Other explanations for the restricted water exchange between stem and tomato fruit should be investigated. In present research we examined macro- and microscopic aspects of water relations of tomato fruits, including changes in apo- and symplastic osmotic pressures and cell pressure (turgor, measured by cell pressure probe) in pericarp tissue of tomato fruit during development and due to water stress aiming to investigate the driving force for water exchange between apo- and symplast at cell level. Turgor pressure in tomato fruit cells was extremely low (< 0.1 MPa), almost constant during fruit development and not influenced by water stress during growth that actually reduced fruit size by 30%. Symplastic osmotic pressures in pericarp tissue slightly increased during fruit development (15 to 50 Days After Anthesis) and increased due to low water availability in the root environment. Apoplastic osmotic pressures in pericarp tissue also increased with fruit development and due to low water availability during growth. A possible role for apoplastic solutes, regulating the water exchange of fruit pericarp cells during growth is proposed.