Vitamin D deficiency is highly prevalent due to lifestyle and environmental factors which limit sunlight induced vitamin D production in the skin. This "pandemic" of vitamin D deficiency is of concern because low levels of 25-hydroxyvitamin D (25[OH]D) have been associated with cardiovascular, musculoskeletal, infectious, autoimmune and malignant diseases. Epidemiological studies have largely but not consistently shown that vitamin D deficiency is a risk factor for strokes. This is supported by associations of low 25(OH)D levels with cerebrovascular risk factors, in particular with arterial hypertension. Vitamin D has also been shown to exert neuroprotective, neuromuscular and osteoprotective effects which may reduce cognitive and functional impairments in poststroke patients. Hence, the current literature favours the notion that vitamin D supplementation is a promising approach for the prevention and treatment of strokes but accurate data from interventional studies are missing. Randomized controlled trials are therefore urgently needed to evaluate whether vitamin D supplementation reduces the incidence of strokes and improves the outcome of poststroke patients. We do, however, believe that currently published data on the multiple health benefits of vitamin D and the easy safe and inexpensive way by which it can be supplemented already argue for the prevention and treatment of vitamin D deficiency in order to reduce stroke associated morbidity and mortality.