Ascites in patients with breast cancer is uncommon. We report the case of a 70-year-old woman with breast cancer and ascites caused by portal hypertension due to metastatic liver infiltration. There was no evidence of peritoneal carcinomatosis and the prothrombin index was normal. Portal hypertension was confirmed by increased hepatic venous pressure gradient. Histological examination of a liver biopsy obtained by the transjugular route demonstrated infiltration by malignant cells from the breast tumor. This case shows that, infiltration of the liver by metastases from breast cancer may lead to ascites due to portal hypertension, even in the absence of hepatic failure.