Portal vein thrombosis as a complication of liver cirrhosis has been reported to be extremely rare in Japan, as compared with European countries. There are few reports discussing the correlation of portal vein thrombosis with refractory ascites. Between January 1994 and December 1995, 20 cases (91%) of 22 patients with liver cirrhosis with ascites admitted to our hospital responded well within 2 months to a combination therapy of diuretics and albumin infusion, and the other two cases (9%) with refractory ascites were associated with portal vein thrombosis. The ascites in the first patient continued for 1 year, despite diuretics and albumin infusion therapy, and portal vein thrombosis was confirmed by autopsy. The ascites in the other patient continued for more than 4 months, and portal vein thrombosis was detected by ultrasound. Portal vein thrombosis was not found in the other 20 cirrhotic patients with ascites. These two cases suggest that portal vein thrombosis may be a contributing factor to refractory ascites in patients with decompensated liver cirrhosis.