Hypothyroidism is not a common cause of overt rhabdomyolysis. We present a patient with subclinical hypothyroidism that led to rhabdomyolysis. A 62-year-old man was admitted to the hospital with a 1-year history of myalgias, fatigue, and muscle weakness. He had dark urine. Muscle enzymes were elevated and he had myoglobinuria. The diagnosis of rhabdomyolysis was made. He also had subclinical hypothyroidism. Thyroxine replacement treatment was initiated. After 4 weeks of treatment, all his symptoms were improved, and after 8 weeks of treatment they had disappeared. Muscle enzymes and thyroid function tests were all in the normal range. © 2008 Lippincott Williams & Wilkins, Inc.