We studied consumption of free water by a sample of 7 Red Tree Voles (Arborimus longicaudus) maintained in captivity on a natural diet of Douglas-fir (Pseudotsuga menziesii) foliage. Mean consumption of free water by individual voles was 0.016 ± 0.001 ml/g/d, which is much lower than has been reported for most other species of voles. The small amount of free water consumed per day suggests that Tree Voles need little access to free water and can obtain nearly all of their water from their diet of conifer needles, which is low in caloric value but high in water content.