Clinical, usually moderate myopathy, frequently develops in patients with hypothyroidism and may reveal the thyroid dysfunction. Biological signs of myolysis, essentially a, usually moderate, rise in creatine phosphokinase plasma levels, are often found. On the other hand, rhabdomyolysis seems to be exceptional in this context. We report a case where an extremely severe clinical and biological myopathy associated with transient renal failure revealed hypothyroidism due to prolonged intake of amiodarone.