Morphologic studies using renal sonography and CT scanning were performed in 6 patients with primary distal renal tubular acidosis who were followed for 6 to 18 years. Nephrocalcinosis and renal cysts were identified in all patients. Multiple bilateral renal cysts were detected in 3 patients, and unilateral single or several renal cysts were detected in 3 patients. Size and number of the renal cysts in 1 patient did not change over 5 years of alkali therapy. Although the precise mechanism for renal cyst formation has not yet been established, renal cysts may be a common complication of primary distal renal tubular acidosis.