Renal transplantation has become an established treatment modality for end-stage renal disease (ESRD) in children, which may allow normal growth and development and enables children to return to a normal lifestyle. In addition, the potential for complications after renal transplantation is far greater in children than in adults. This study was designed to determine the clinical outcome of kidney transplantation in pediatrics. We retrospectively reviewed the medical records of pediatric kidney recipients who received a living kidney transplant at two renal transplantation centers in Tehran, Iran, between November 1985 and November 2006. Recipients were defined as "pediatric" if they were 18 years of age or younger. Our study involved 539 pediatric recipients (58.1% male and 41.9% female). The mean age of recipients and their donors were 13.5±3.7 and 27.5 ± 5.8 years, respectively. The median patient follow up was 34.4 (0.3 - 226.8) months. The common cause of ESRD was glomerulonephritis (33.1%), followed by urological problems (30.5%) and congenital disorders (9.1%). The majority of patients had a living unrelated donor (80.7%). The prevalence of hepatitis B and C among our recipients was 1% and 4.4%, respectively. The mean of last serum creatinine level was 1.7 ± 1.4 (range 0.2-10.6) mg/dl. One, five, ten, fifteen and eighteen-year patient survival rates were 92%, 88%, 84%, 63%, and 63%, respectively. Also, One, five, ten, fifteen and eighteen-year allograft survival rates were 77%, 57%, 41%, 23%, and 15%, respectively. Our study showed that kidney transplantation is promising in children requiring renal replacement therapy.