Hypoxaemia is an essential component of hepato-pulmonary syndrome (HPS) in patients with portal hypertension. An underlying pathology in HPS is an imbalance between vascular dilatators and constrictors, resulting in vaso-dilatation at the level of pulmonary microcirculation. This leads to arterio-venous pulmonary shunt and a decline in oxygenation of arterial blood in the systemic circulation. Hepato-pulmonary syndrome may develop on the basis of various chronic liver diseases, and clinical symptoms of this syndrome are a combination of hepatic failure, portal hypertension and lung dysfunction. The diagnosis requires confirmation of intrapulmonary vascular dilatations with contrast echocardiography or albumin lung-brain scintigraphy. Diagnosis of HPS carries a poor prognosis. Despite many clinical trials with different pharmacological compounds, up to now there is no effective medication of HPS. The best treatment of HPS remains liver transplan-tation. In this paper we present clinical aspects of HPS, taking into account the pathogenetic background of this portal hypertensive complication