Restless legs syndrome (RLS) has been thought to be a basically neurological disorder, often observed among patients with sleep disturbance. Although the disease identity was proposed more than half a century ago, the pathogenesis of RLS has not been elucidated, and high prevalence of the disease has been demonstrated in many reports. I hypothesize that the crucial event for the occurrence of unpleasant sensations in the legs at night should be the change of blood flow dynamics. Acceleration of blood flow in the legs when lying down should stimulate nerve fibres which are closely located to the blood vessels. This hypothesis can explain many aspects of RLS, including symptoms as well as epidemiological findings. Treatment utilizing vitamin E might be extremely easy, safe, and inexpensive compared with the dopaminergic agents or opioids usually recommended for treatment.