Background: Spontaneous bacterial pleuritis is a high mortality complication in cirrhotic patients with hydrothorax. Aim: To investigate the prevalence and risk factors for spontaneous bacterial pleuritis in cirrhotic patients with hydrothorax. Methods: Adult inpatients with liver cirrhosis and hydrothorax were enrolled. The severity of liver disease was assessed by the Model for End-Stage Liver Disease (MELD) score. Pleural fluid was analyzed [pH, polymorphonuclear (PMN) leucocyte count, total protein level, lactate dehydrogenase (LDH) level, glucose level, bacterial culture and cytology]. Spontaneous bacterial pleuritis was diagnosed by positive pleural fluid culture or, if negative, a pleural fluid PMN count >500 cells/μL without radiographic evidence of pneumonia. Results: Out of 98 cirrhotic patients with hydrothorax enrolled in the study; 14 (14.3%) fullfilled the criteria for the diagnosis of spontaneous bacterial pleuritis. Of those 14 patients; 9 were culture positive and 5 were culture negative. The other 84 did not have evidence of spontaneous bacterial pleuritis and were considered to have uncomplicated hydrothorax. Patients with spontaneous bacterial pleuritis had more severe liver diseases (MELD score), and higher rate of associated spontaneous bacterial peritonitis (SBP) and bacteraemia than patients with uncomplicated hydrothorax. Patients with spontaneous bacterial pleuritis had a significantly higher PMN count and a lower protein level in the pleural fluid. Conclusion: The prevalence of spontaneous bacterial pleuritis in the studied group of patients with hepatic hydrothorax was 14.3%. Patients with advanced liver disease, low pleural fluid protein, or SBP are at risk for spontaneous bacterial pleuritis.