Raynaud's phenomenon is commonly induced in chain-saw operators by vibration; the hand guiding the tool is the more severely affected. The condition tends to persist after use of the chain-saw is stopped but compensation is rarely sought. Among 17 cases of Raynaud's phenomenon in lumberjacks the condition was found to be related to use of the chain-saw in 14, 10 of whom had to give up their work in colder weather because the disease was so disabling. Two criteria essential to establish the condition as vibration-induced Raynaud's phenomenon are the presence of symptoms for at least 2 years and a history of at least 1 year's constant use of the chain-saw. Careful physical examination and simple tests of vascular function will provide objective evidence of permanent damage by which the patients may be classified and compensated.