In 105 patients CT studies were done prospectively after renal ESWL with a second generation lithotripter. 33 (31%) of the patients had renal oedema (n = 8), renal (n = 20) or extrarenal (n = 31) bleeding. Three of the 23 patients who had a three year follow-up had chronic renal changes, 10 had renal stones. As blunt renal trauma can be the cause of renal hypertension a longterm follow-up is necessary in ESWL patients, particularly if there was renal bleeding after treatment. Further studies are needed to determine the exact risk of renal hypertension after ESWL.