We investigated urinary catecholamines' response to acute psychological stress test in hand-arm vibration syndrome patients. Thirteen patients with vibration-induced white finger (VWF) in higher frequency of attack, 7 patients with VWF in lower frequency, 6 patients without VWF and 17 healthy subjects were examined. All subjects were male and their average age (SD) was 59.2 (6.4), 56.3 (2.9), 58.2 (4.7) and 56.8 (4.9), respectively. After an initial rest for 1 hour, acute psychological stress test with stressors--mirror drawing, watching horror video and arithmetic under intermittent noise was performed for 1 hour. Subjective complaints to the stress test were greater in patients with hand-arm vibration syndrome than in the healthy controls. The patient group with VWF in higher frequency indicated significant increases of urinary catecholamines (p < 0.05); average values (SD) at rest period and at stress test were 2.42 (1.17) and 3.71 (1.82) micrograms/h for norepinephrine, and 1.47 (0.73) and 2.66 (1.79) micrograms/h for epinephrine, respectively. Increasing tendency of urinary catecholamines was observed in other three groups, however, they were not statistically significant. The sympathoadrenal medullary response to psychological stressors increased especially in hand-arm vibration syndrome patients with VWF in higher frequency.