The aim of this study was to study the prevalence of hepatopulmonary syndrome (HPS) in cirrhotic patients, comparing the results obtained using contrast transthoracic echocardiography (CTTE) and contrast transesophageal echocardiography (CTEE) in the demonstration and grading of pulmonary vasodilatation (PV). We also analyzed the correlation between gas-exchange abnormalities and PV when it was demonstrated with both techniques. The prevalence of PV and HPS with CTEE in the 88 cirrhotic patients was 28% and 22%, respectively, and with CTEE, 42% (P < 0.05) (middle PV: 35% and significant PV: 7%) and 30% (P < 0.05), respectively. Fifty-six percent of patients diagnosed with PV and with CTTE presented with hypoxemia as did 49% using CTEE (83% of patients with significant PV had hypoxaemia). PaCO2 and diffusing capacity of CO were significantly more decreased in patients with PV than in patients without PV when CTEE was employed. We conclude that CTEE is superior to CTTE in the diagnosis and grading of PV in the diagnosis of HPS in cirrhotic patients, being more sensitive and presenting a better correlation with gas-exchange abnormalities. Given its high sensitivity, CTEE should be carried out in all patients with suspicion of HPS and normal or uncertain CTTE.