Distal renal tubular acidosis (DRTA) is frequently associated with immune-mediated diseases such as sys- temic lupus erythematosus (SLE), Sjogren's syndrome, idiopathic hypergammaglobulinemia, autoimmune liver diseases, autoimmune thyroid diseases, renal transplant rejection, rheumatoid arthritis, and ankylosing spondylitis. We report two cases of distal renal tubular acidosis associated with immune-mediated diseases. The first case was a patient with SLE, who had general weakness, vomiting, and hypokalemia, and the second case was a patient with Sjogren syndrome, who had quadriparesis, respiratory arrest, and hypokalemia. DRTA was diagnosed with short-term NH4C1 loading tests in both patients. In the second case, we performed NaHCO3, test, which reconfirmed DRTA. The mechanism of DRTA, confirmed by 4% Na2SO4 loading tests, was a hydrogen ion secretory pump defect in both patients. We discussed the mechanisms of DRTA and the methods that could differentiate the mechanisms, and the frequencies and the pathogenesis of DRTA in SLE and in Sj5gren syndrome.