Pulmonary hypertension associated with mitral valve disease can significantly complicate mitral valve replacement. Nitric oxide (NO) has an established role in congenital heart surgery and in cardiac transplantation. However the evidence to date suggests that iNO does not provide a clinical advantage in pulmonary hypertension associated with valvular heart disease. We discuss a 56-year-old male with acute mitral incompetence who underwent emergency surgery. Following mitral valve replacement he was weaned off cardiopulmonary bypass with an intra-aortic balloon pump and high doses of inotropic support but continued to be hypotensive. Inspection of the heart showed right-sided dysfunction and evidence of pulmonary hypertension. Following the introduction of iNO he rapidly improved. He was successfully separated from the cardiopulmonary bypass support and subsequently made a full recovery and was discharged. We believe that this case demonstrates the utility of iNO in the management of pulmonary hypertension secondary to valvular disease in the acute setting. This is in contrast to the evidence against its utility in established pulmonary hypertension in chronic valvular heart disease. Further confirmation of this observation may lead to the therapeutic use of NO in this subpopulation of cardiac surgery patients.