Renal stone and nephrocalcinosis are common clinical manifestations of type 1 renal tubular acidosis. In normal state, citrate plays the most critical role in suppressing stone formation as it combines with calcium. In type 1 RTA, increased reabsorption of citrate in proximal tubule results in low citrate excretion, which precipitates renal stone formation. We report a case of type 1 RTA accompanying renal stone and nephrocalcinosis caused by hypocitraturia. A 16-year-old male patient who had renal stone and nephrocalcinosis showed hypocitraturia. Incomplete type 1 RTA was proved as the cause of hypocitraturia by bicarbonate and ammonium loading test in the patient.