After transplantation (Tx), both children with an underlying nephrological disease and children with an underlying urological disease, might have a dysfunctional lower urinary tract along with a substantially increased bladder capacity and urinary tract infections. This may lead to a deterioration of renal function.The nurse practitioner coordinates the urological follow up. Before Tx urological evaluation takes place (T0). After Tx, two days after the indwelling catheter is removed a second urological evaluation takes place (T1). To prevent dysfunctional voiding and increased bladder capacity, micturition training starts. To minimize a postvoiding residual (PVR), it is important that the child performs double voiding at least twice a day. 13 weeks after TX the third urological evaluation takes place (T2). Findings are discussed in a multidisciplinairy meeting. At least once a year micturition follow up will be performed with frequency/volume chart, uroflowmetry, PVR and urinary cultures and in the case of a large or a small bladder capacity, PVR and UTI's urodynamic investigations.A pilot study showed that most of the transplanted children, with or without former dialysis treatment or underlying urological disease, had abnormal voiding habits. In some children urodynamic or other investigations were necessary. Voiding techniques were improved by our training program. Increase of the awareness and knowledge of adequate voiding related to Tx was an important effect of this pilot. In January 2007 we started the active training and follow up protocol.Close urological follow-up with active training of normal voiding habits directly after renal Tx in children is necessary to prevent a dysfunctional lower urinary tract along with a substantially increased bladder capacity and urinary tract infections, which may harm the graft. Our follow-up study will show whether there is also improvement of long term graft survival