BACKGROUND/AIMS: Paracentesis is an acceptable therapeutic modality for the symptomatic relief of dyspnea or abdominal fullness due to tense ascites in patients with cirrhosis. Whereas studies about the effects of paracentesis focused on the changes about hemodynamics, electrolytes and renal function in great detail, the effects of paracentesis on the changes about respiratory system have undergone limited investigations which are defined large-volume paracentesis. METHODS: We performed pulmonary function tests with arterial blood gas analysis just before and 24 hr after paracentesis. The paracentesis of average 2,300ml was carried out in ten liver cirrhosis patients with tense ascites who were free from underlying cardiopulmonary impairment. RESULTS: 1. The results of pulmonary function test just before paracentesis were as followings; FVC( functional vital capacity), FEV1(forced expiratory volume in 1 sec), FEF25 75(forced expiratory effort 25% 75%) and TLC(total lung capacity) were decreased as 78%, 79%, 62.3% and 89% of normal control value respectively, whereas RV(residual volume) was not decreased. DLCO(lung diffusion capacity of carbon monoxide)was decreased as 61.6%. 2. The results of pulmona function test 24 hr after paracentesis were as followings,' The symptomatic relief of dyspnea was achieved in all participated ten patients. Among lung volume parameters, FVC and VC were increased significantly(p=0.003, p=0.004). Whereas TLC was increased without statistical significance(p=0.228), and RV and FRC(functional residual capacity) showed no change. FEV1 was increased significantly(p=0.039), but FEF25 75 and the ratio of FEF1/FVC showed no change. DLCO was not increased. PaOy(partial pressure of oxygen in arterial blood) was impr'oved without statistical significance. CONCLUSIONS: These results suggest that the patients of liver cirrhosis with ascites have restrictive ventilatory impairment with additional obstructive ventilatory impairment. After paracentesis, the restrictive ventilatop impairment is improved by the relief of diaphragmatic motion limitation caused by ascites. Also, paracentesis of(not large volume, like 5000ml, but) relatively small volume, of 2000 3000ml can achieve objective improvement of dyspnea due to tense ascites.