An experience with 103 children treated with extracorporeal shock wave lithotripsy (ESWL) is reviewed in this report. The success rate was 63%. The stone volume was of major importance for the result. There was a continuous decrease in success rate with increasing stone size. It was also shown that stone-free rates decreased with an increasing number of stones. Short-term complications were minor and hospitalization times were short. It is concluded that ESWL is a first-choice treatment in children with urinary calculi smaller than 200 mm(2) in size.