Restless legs syndrome (RLS) is a poorly understood sleep-related movement disorder which can be primary or associated with other conditions, most commonly iron deficiency, uremia and peripheral nerve disease. We present a case of RLS with an unusual secondary cause: primary hyperparathyroidism with hypercalcemia. This patient experienced complete and sustained relief of RLS symptoms immediately after parathyroidectomy, with normalization of her serum parathyroid hormone (PTH) and calcium levels. Early recognition and treatment of this uncommonly detected underlying cause is important because it is potentially curative in this frequently disabling condition for which usually only symptomatic treatment is available.