To describe the clinical and laboratory features of rheumatoid pleural effusion (RPE) and the diagnostic and therapeutic approaches to this condition.The review is based on a MEDLINE (PubMed) search of the English literature from 1964 to 2005, using the keywords "rheumatoid arthritis" (RA), "pulmonary complication", "pleural effusion", and "empyema".Pleural effusion is common in middle-aged men with RA and positive rheumatoid factor (RF). It has features of an exudate and a high RF titer. Underlying lung pathology is common. Generally RPE is small and resolves spontaneously but symptomatic RPE may require thoracocentesis. Rarely, RPE has features of a sterile empyematous exudate with high lipids and lactate dehydrogenase, and very low glucose and pH levels. This type of effusion eventually leads to fibrothorax and lung restriction. Superimposed infective empyema often complicates RPE. Oral, parenteral, and intrapleural corticosteroids, pleurodesis and decortication, have been used for the treatment of sterile RPE. Infected empyema is treated with drainage and antibiotics.RPE may evolve into a sterile empyematous exudate with the development of fibrothorax. Symptomatic effusions or suspicion of other causes of exudate (infection, malignancy) require thoracocentesis. The "rheumatoid" nature of the pleural exudate in patients without arthritis mandates a pleural biopsy to exclude tuberculosis or malignancy. The optimal therapy of RPE has yet to be established. The role of cytokines in the course of RPE and the possible usefulness of cytokine blockade in the treatment of this RA complication require further evaluation.