A retrospective study evaluated posttransplant growth of 70 prepubertal children during the first 2 y after renal transplantation (RTx). Immunosuppressive treatment consisted of prednisone administered either daily or on alternate days in combination with either azathioprine or cyclosporin A. The increment in height standard deviation score for chronologic age during the first 2 y after RTx was less than 0.5 SD for 70% of the study population. The predictive factors for posttransplant growth were determined by evaluating several factors and treatment modalities singly and simultaneously in a multiple regression analysis. Patients with the most severe growth retardation at RTx appeared to have the most pronounced growth spurt after RTx, but even they never had complete catch-up growth, and 2 y after RTx they were still shorter than those with less severe growth retardation at RTx. Alternate-day instead of daily prednisone administration had a significantly positive influence, whereas a high cumulative dose of prednisone, azathioprine instead of cyclosporin A therapy, and a persistently reduced GFR (GFR < 50 mL/min/1.73 m2) had a significantly negative influence on catch-up growth during the 2 y after RTx. Other factors, such as gender, chronologic and bone age at RTx, primary renal disease, duration of initial dialysis, repeat RTx, and target height SD score for chronologic age, whether evaluated singly or simultaneously with other significant factors, appeared to have no significant influence on post-RTx growth. Thus, 70% of the prepubertal children do not experience appreciable catch-up growth during the first 2 y after RTx. Optimization of pretransplant height appears very important. Immunosuppressive treatment with cyclosporin therapy in combination with a minimal dose of alternate-day prednisone would then result in optimal post-transplant growth, particularly if the GFR remains above 50 mL/min/1.73 m2).