Patients with rheumatoid arthritis of any degree of severity or duration may develop necrotizing granulomatous pleuritis, a morphologic replica of the inflammatory reaction characteristic of rheumatoid synovitis and rheumatoid nodules. The principal feature is the background composed of granular, amorphous, particulate material or debris of various hues. The material is sometimes eosinophilic sometimes more cyanophilic, or even green in the Papanicolaou stain. Within this background are elongated, fibroblast-like epithelioid cells, numerous multinucleated giant cells and degenerating leukocytes. The combination of the debris, spindle epithelioid ceils, and multinucleated giant cells in fluid is pathognomonic for rheumatoid pleuritis. We experienced a hcase of rheumatoid pleuritis showing these characteristic cytologic findings. The patient was a 63 year-old man with positive rheumatoid factor. The pleual fluid specimen revealed elongated epithelioid cells and multinucleated giant cells on a background of amorphous granular material.