Pulmonary function (FVC, FEV1, PEFR, MMEF) and arterial blood gases (ABG) were analysed in 30 patients of portal hypertension. The aetiology of portal hypertension included cirrhosis of liver (n = 10), non cirrhotic portal fibrosis (NCPF, n = 10) and extrahepatic portal vein obstruction (EHPVO). Ten patients with chronic active hepatitis (CAH) without portal hypertension were also studied. Most pulmonary functions were abnormal (low) in portal hypertension and the most affected parameters, were FEV1, PEFR and MMEF (p < 0.05). The same was also observed in CAH, although in less number of patients. Hypoaxemia (26.7%) and wide alveolar--arterial oxygen gradient were observed most frequently in patients of portal hypertension. These patients also had a more alkaline blood pH. EHPVO patients had better lung function and arterial blood gas values. Patients with NCPF had greater impairment in pulmonary function.