A 62-year-old female patient with a 20-year history of RA had been on methotrexate, leflunomide, and prednisone. Because the articular inflammatory process persisted, we decided to start the patient on adalimumab, continuing her on methotrexate. A chest X-ray showed no changes suggestive of previous tuberculosis or signs of incipient ILD; and the intradermal (PPD) test for tuberculosis was negative (0 mm). One week after receiving the second dose of adalimumab (40 mg weekly), the patient started experiencing dry cough, dyspnea on moderate exertion, and daily fever (38 C). At that point, the results of chest X-ray, physical examination, and laboratory tests, including blood workup, were normal-hemoglobin, 13.1 g/dL; hematocrit, 39.2%; 8,380 leukocytes (75% neutrophils, 0.4% eosinophil, 9.8% lymphocytes); and 355,000 platelets, except for an increase in inflammatory markers (C-reactive protein, 326 mg/dL; reference value < 3 mg/dL) and in ESR (67 mm, reference value < 20.2 mm). Sputum smears for AFB and blood cultures were negative. The patient was started on empiric treatment with levofloxacin; however, she continued to have fever and dyspnea. A HRCT scan of the chest, performed two weeks after symptom onset, revealed ground-glass opacities, predominantly in the upper and middle lung fields, associated with areas of smooth interlobular septal thickening (Figure 1). Therefore, a presumptive diagnosis of ILD secondary to the use of adalimumab was made. We decided to discontinue the patient from the anti-TNF agent and methotrexate and to continue her on low-dose prednisone (5 mg/day). The patient showed progressive reduction in dyspnea, remission of fever, and normalization of inflammatory markers, without reactivation of the articular inflammatory process. Three weeks after the onset of the condition, the results of physical examination and spirometry were normal, with an SpO2 of 98% on room air. A second HRCT, performed three weeks after symptom onset, showed near-complete resolution of the ground-glass areas (Figure 2).