Vibration hazards which arise after exposure to mechanical vibration comprise various types of disorders, the most common of which are peripheral circulatory disturbances. It is now well recognized that aging effects all organ systems of the human body. The present study was therefore performed to assess the effects of aging on finger skin temperature and on hyperemia time after pressing the nail, both of which reflect peripheral circulatory functions. The subjects were 88 farmers and 86 chain saw operators ranging in age from 30 to 69 years, and 27 healthy persons aged 21 to 37 years as controls. Data were evaluated before and after cold water immersion tests in which the hand was immersed in 10 degrees C water for 10 minutes. The results obtained were as follows: 1) Before the test, skin temperature was negatively correlated with age, and hyperemia time was positively correlated with age in both farmers and chain saw operators but not in the case of the control subjects. 2)The skin temperature became lower, and hyperemia time grew longer with advancing age in both farmers and chain saw operators before and after the immersion tests. In comparison of the average skin temperature and hyperemia time between farmers and chain saw operators classified by age, the average skin temperature in chain saw operators was significantly lower than that in farmers, and the average hyperemia time in chain saw operators was significantly longer than that in farmers of every age group after the immersion test. The results suggest that we should take age-related changes into consideration to some degree when we evaluate the finger skin temperature and hyperemia time in diagnosing peripheral circulatory disturbances.