Hypokalemic periodic paralysis is an uncommon complication of thyrotoxicosis, and very rare as a presenting symptom. It is most frequent in east Asian and Japanese males, but extremely rare in others. Only 1 case has previously been reported from Israel. We present a 29-year-old Arab man who presented with sudden paralysis of both legs. Physical examination revealed signs of thyrotoxicosis, and laboratory tests showed profound hypokalemia. Oral potassium resulted in rapid disappearance of symptoms, and after restoration of the euthyroid state, there were no further attacks. This case shows that thyrotoxic hypokalemic periodic paralysis is not confined to males of east Asian and Japanese origin, and that adequate treatment with oral potassium and antithyroid drugs is successful, and should be given as soon as possible.