Thyrotoxic periodic paralysis (TPP) is characterized by the presence of muscle paralysis, hypokalemia, and hyperthyroidism. We report the case of a young man with paralysis of the lower extremities, severe hypokalemia, and concurrent hyperthyroidism. TPP was suspected; therefore, treatment consisting of judicious potassium (K+) repletion and β-blocker administration was initiated. However, urinary K+ excretion rate, as well as refractoriness to treatment, was inconsistent with TPP. Chronic alcoholism was considered as an alternative cause of hypokalemia, and serum K+ was restored through vigorous K repletion and the addition of K+ -sparing diuretics. The presence of thyrotoxicosis and hypokalemia does not always indicate a diagnosis of TPP. Exclusion of TPP can be accomplished by immediate evaluation of urinary K+ excretion, acid-base status, and the amount of potassium chloride required to correct hypokalemia at presentation.