Hepatic hydrothorax is defined as a pleural effusion in patients with liver cirrhosis without primary cardiac, pulmonary or pleural disease. It is a rare but important cause of unilateral-pleural effusion. The prevalence of this complication is 5-10% of the total number of patients with advanced stages of cirrhosis. In most cases (85%), the effusion is right-sided; however, in 13% of cases it can be left-sided and bilateral in 2% of the cases. We present a case of left-sided hepatic hydrothorax in the absence of ascites in a patient with primary biliary cirrhosis. The diagnosis of cirrhosis was confirmed by the biopsy;the patient didn't have any history or any signs or symptoms of cirrhosis prior to her presentation. In the case described, the patient was treated with spirnolactone, furosemide and ursodeoxycholic acid. At follow-up after six months since the diagnosis, she was responding to treatment with no complications. This case emphasizes the importance of considering hepatic hydrothorax as an etiology of a transudative pleural effusion regardless of the presence or absence of ascites inpatients with occult cirrhosis.