A 72 year old female with rheumatoid arthritis was treated with methotrexate for nine months. Four days before admission she complained of dyspnea NYHA III. Chest-X-ray revealed diffuse interstitial pneumopathy. Pulmonary infection was excluded by several microbiological samples. A pulmonary manifestation of rheumatoid arthritis is usually more chronic. Methotrexate-induced pneumonitis remained the most probable diagnosis. We halted methotrexate and initiated therapy with glucocorticoids. This treatment led to rapid clinical improvement and complete resolution of radiological changes.