A fourth case of symptomatic porphyria associated with hemodialysis for chronic renal failure is reported. Subepidermal bullous dermatoses of patients who have undergone hemodialysis have not usually been associated with elevated porphyrin levels. However, this patient and three previously reported cases have been found to have abnormal porphyrin study results in association with skin lesions typical for porphyria cutanea tarda, occurring after hemodialysis. Hemodialysis does not effectively decrease circulating plasma uroporphyrin levels, although some dialysis of uroporphyrin into the dialysate could be measured in this case. Evaluation of bullous or porphyrialike dermatoses in patients treated with hemodialysis should include adequate testing for increased porphyrin levels.