Because of its ballistic and physical characteristics, brachytherapy (BT) represents the optimal irradiation treatment in pediatric tumors, especially in prostate or bladder rhabdomyosarcoma. In a limited series of 15 children treated with BT (including three patients treated with salvage BT), 8 out of 9 patients surviving with NED benefited from conservative treatment among 12 patients treated with BT as first-line treatment. Sequelae were minimal consisting of one grade I cystitis and one asymptomatic vesical and ureteral reflux. BT allows administration of high doses to limited volumes sparing normal tissues. BT--whenever possible--represents the treatment of choice compared with external radiotherapy. Indications of BT depend on tumor accessibility and size (usually < or = 4 cm).