One year of increased salt intake in monkeys elevates mean blood pressure significantly. This effect is more marked in animals exposed just after birth. In animals exposed as adults, the response in males is more pronounced than in females, mainly due to a marked increase of pulse pressure. Th hypertensive response was potentiated by reduction of renal mass, which caused GFR values (in terms of body weight) to decrease compared with intact salt-fed animals, in which GFR values were elevated above the control level. It is concluded that the mechanisms involved in the hypertensive response are similar to those in the rat and dog.