Raynaud's phenomenon (RP) is a vasospastic condition of the extremities in response to cold or stress, affecting approximately 3% to 5% of the population. While most patients have primary RP, the condition can also occur secondary to a variety of underlying medical conditions. RP may be the presenting symptom of connective tissue diseases, especially systemic sclerosis, and RS may therefore provide an opportunity for early diagnosis and treatment. This review addresses the causes, clinical features, diagnostic workup, and treatment possibilities of RS.