Malignant pleural effusion is one of the most common problems that chest physicians face in their everyday practice. The diagnosis of malignant pleural effusion requires either a histological or cytological demonstration of malignant cells in the pleural tissue or pleural fluid. Medical thoracoscopy allows direct visualization of the pleural surfaces, allowing pleural biopsies, removal of pleural fluid and pleurodesis, often using talc insufflation. The most common indication for thoracoscopy is evaluation of the undiagnosed exudative pleural effusions. When performed by well-trained personnel, thoracoscopy is a safe and well tolerated procedure.