Current therapy of persistent pulmonary hypertension of the newborn (PPHN) consists of optimal ventilation, hemodynamic support and selective vasodilatation with inhaled nitric oxide (iNO). We present herein a case of PPHN non-responsive to iNO but treated successfully with a combination of iNO and intravenous milrinone, a phosphodiesterase III inhibitor. This case suggests that the drug may be a useful adjunctive treatment in the management of PPHN.