The treatment of choice in end-stage renal disease (ESRD) in children and adolescents is kidney transplantation, which can improve the patients’ growth, development, and quality of life. Most of the studies carried out on the subject to date have been descriptive rather than comparative; moreover, there have been few studies on the difference in the outcome between younger age groups and older ones. We sought to investigate patient and graft survival in a comparative study of pediatric and adult kidney recipients.In this crosssectional study, 2631 Iranian kidney recipients who had undergone kidney transplantation in Baqiyatallah or Labbafinegad Hospitals between 1982 and 2002 were studied. The patients were divided into pediatric group (n=301, age 18 or less) and adult group (n=2330, age over 18). Graft survival was analyzed uncensored for death (death with a functioning graft was considered as an event). The mean age of pediatric and adult groups was 40.05±13.60 and 13.92±13.17, respectively. Five years survival of the graft was 68% in pediatric group and 56% in adult group (p=0.015). Patient survival was 88% and 86%, in pediatric and adult groups, retrospectively (p>0.05). Our results demonstrate that while there in no significant difference in terms of patient survival after kidney transplantation between pediatric and adult recipients, long term graft survival in the is poorer in those with the pediatric patients, which is probably due to the difference in the function of the immune system, different underlying causes of ESRD and their duration, and the duration of dialysis before kidney transplantation.