The aim of this study was to evaluate the efficacy of high-pressure balloon dilatation (HPBD) as treatment of primary obstructive megaureter in paediatric patients. HPBD proved to be a safe, feasible and minimally invasive technique to treat primary obstructive megaureter with surgical criteria, even under 1 year of age. In comparison with standard surgery, HPBD has the advantages of being a less invasive procedure with no patient-age limitations. In our opinion, the HPBD may be utilised as first-line treatment in the management of primary obstructive megaureter in children, avoiding unnecessary bladder surgery in most cases. In any case, this technique does not influence conventional surgery in the case of failure.