Assessment of catch–up growth of children after renal transplantation by analyzing the 6 months changes in height deficit and height standard deviation scores (SDS) on age, sex, initial height deficit, initial SDS, graft function, renal failure duration and renal transplantation duration. Between 22 September 1999 and 2000, 25 pediatric recipients followed up quarterly for height in the Labafi – Nejad Hospital. Data on height submitted at each 6 – month follow-up were converted into height deficit and SDS. All the results were analyzed by simple and multiple regression and t – test. 68% were male and 32% were female. Mean age at transplantation was 10.39±2.95 SD years. The average duration of renal transplantation was 20.7 8.96± SD months. 10 transplanted preemptively and 15 were hemodyalized for 17.64 mean 10.93± SD months. The average of height deficit was – 20.7 cm (10.55 ± SD) and SDS -3.5 1.72 ±) SD) at the time of renal transplantation. The height deficit was more significant in the patients with tubulopathy disorders that fluid and electrolyte imbalance and acidosis was more severe. 80 % at months 18 - 24 had creatinine clearance above 80 ml / min. Catch – up growth observed at month 12. That was more obvious in females, in patients with tubulopathy disorders, in preemptive and in all three age groups. Simple and stepwise regression analysis showed that at month 12 only initial height deficit (p<0.05), at month 18, height deficit at the time of transplantation (p<0.05) and renal failure duration (p<0.05) were independent predictors of catch – up growth. At month 24, only sex (p<0.05) was independent predictor of improved height post transplantation. Catch–up growth were seen in more stunted patients & girls. This may be the result of puberty spurt that occurs two years sooner in girls than in boys. Children more than 5 years old do not show complete catch-up growth after renal transplantation. It is necessary to think about other ways to improve height in pediatric recipients.