Raynaud's phenomenon is episodic digital ischemia provoked by cold and emotion; it is associated with other disorders, such as Raynaud's syndrome, especially the connective tissue diseases. Recent information suggests links with Sjögren's syndrome, malignancy, and obstructive vascular disease. The vasospasm can affect areas outside the periphery such as the inner ear in vibration white finger syndrome and the placental vessels in pregnancy. The initial presence of autoantibodies increases the chance by 63-fold of developing connective tissue diseases, and such immunologic testing can be usefully combined with nailfold vessel microscopy. Several factors are considered to be of etiologic importance in Raynaud's phenomenon, such as the augmenting effect of cold on the responsiveness of alpha 2-adrenoceptors to agonists. Deficiency in the vasodilator neuropeptide calcitonin gene-related peptide has been detected, as have excess amounts of the vasoconstrictor endothelin. Treatment of vasospasm remains symptomatic, and directed towards the vasospasm and altered blood constituents.