We report a case of thyrotoxic hypokalemic periodic paralysis occurring in a black man. This previously healthy 41-year-old man had a 3-year history of recurrent paroxysmal episodes of paresis in the upper and lower extremities proximally, often occurring after heavy exercise. The patient had no history of hyperthyroidism, nor family history of periodic paralysis. This case reveals a particularly rare characteristic of this disorder in which periodic paralysis is the presenting symptom of hyperthyroidism. This condition has been reported most commonly among Asians and is extremely rare in black men, only five cases having been described during the past 30 years.