Objectives: The long-term effects of shock wave lithotripsy on the growth of pediatric kidneys are not well defined. Likewise, no long-term data regarding renal growth after ureteroscopy or percutaneous nephrolithotomy have been published. We studied the effect of urolithiasis on renal growth in our pediatric patient population. Methods: A total of 165 children were treated for urolithiasis at St. Louis Children's Hospital from March 1993 to December 2003. Of these 165 children, 74 were available for long-term follow-up. Four groups were evaluated: those who underwent shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy, and those who received no intervention. The expected renal length was calculated using Chen's nomogram, and the observed renal length was measured using renal ultrasonography. All measurements were performed by one pediatric radiologist. The expected and observed renal growth was determined by subtracting the renal length at baseline from the length at follow-up, divided by the number of months of follow-up. Statistical analysis used paired data for each treatment group, and comparisons were made on a nonparametric single-rank method. Results: Of the 74 children, 39 were boys and 35 were girls, with a mean age at treatment of 9 years (range 9 months to 14 years) and a mean follow-up of 6.2 years (range 1.3 to 13.1). In all groups, the comparison between the treated side and nontreated side for expected and actual kidney size and growth was calculated as described. None of the groups had statistically significant differences in the observed or predicted renal growth rates. Conclusions: Shock wave lithotripsy, ureteroscopic stone extraction, and percutaneous nephrolithotomy do not appear to impair renal growth.