Cross-sectional samples (6mm thick) of Scots pine and beech sapwood were immersed in one of four water-repellent formulations consisting of solutions in white spirit of: a) 10% aliphatic hydrocarbon resin, or resin plus 1%; b) paraffin wax (melting point 56°C); c) microcrystalline wax (85°); or d) crystalline paraffin (115°). Water repellency effectiveness was based on swelling data determined at water temperatures of 20, 40, 60 and 80°. Diffusion coefficients were calculated from swelling data to indicate rate of water penetration in relation to treatment. The increase of water temperature from 20 to 80° led to a significant decrease in water repellency in both species. At 20°, water repellency was most effective in (b); at other temperatures (d) was most effective. Differences in water repellency effectiveness between formulations were greater in pine than in beech. In beech, the formulations were almost equally effective at all water temperatures tested.