Aim: To describe the clinical approach to term and near-term newborn infants with severe hyperbilirubinaemia and to analyse the effect of high-intensity phototherapy on total serum bilirubin (TSB) levels. Methods: We analysed a cohort of 116 newborn infants with severe nonhaemolytic hyperbilirubinaemia (TSB‡20 mg⁄dL⁄342lmol⁄L). All patients were treated with high-intensity phototherapy. The main outcomes were reduction in TSB levels in the first 24 h of phototherapy, incidence of exchange transfusion, pathological brainstem auditory evoked responses and pathological findings on neurological examination at discharge. Results: The mean birth weight and gestational age were 3161 ± 466 g and 37.8 ± 1.6 weeks. Mean initial TSB concentration was 22.4 ± 2.4 mg⁄dL. Per cent decreases in TSB after 2, 4, 6, 12, 18 and 24 h of phototherapy were 9.4%, 16%, 23%, 40%, 44% and 50%, respectively. No infant was treated with exchange transfusion. Brain-stem evoked response audiometry (BAER) was performed in 100% of the patients, and in three of them, this examination was altered. However, when repeated 3 months later, these BAER examinations were normal. Neurological examination was normal in all patients. Conclusions: High-intensity phototherapy significantly reduces TSB in nonhaemolytic severe hyperbilirubinaemia and decreases the need for exchange transfusion.