Iloprost, a prostacyclin analogue administered by inhalation, improves hemodynamic and functional class variables in patients with primary pulmonary hypertension. However, repetitive inhalations are required due to its short term effects. One potential approach to prolong and increase the effects of aerosolized iloprost might be to combine its use with phosphodiesterase inhibitors. We report a 36 years old female patient with primary pulmonary hypertension treated with this combination. After 18 months of therapy the patient had an improvement in functional class and in the 6 min walk distance despite persistence of high pulmonary pressures. Our case is in agreement with the reported beneficial effect of the association of sildenafil and iloprost. We postulate that functional improvement in primary pulmonary hypertension is not always related to a decrease in pulmonary artery pressure (Rev Méd Chile 2004; 132: 353-6).