A 68-year-old man with multiple myeloma was admitted to our hospital complaining of slight fever and dyspnea on effort 4 months after treatment with thalidomide. Chest HRCT findings showed diffuse ground-glass attenuation, small nodules, and interlobular septal thickening in bilateral lungs. BAL showed marked lymphocytosis, and TBLB revealed alveolitis with exudative change, consistent with drug-induced interstitial pneumonitis. His thalidomide treatment was withdrawn and his symptoms and HRCT findings improved. Therefore, we diagnosed thalidomide-induced interstitial pneumonitis. Thalidomide-induced interstitial pneumonitis is rare, and only 4 cases have been reported in the literature. We concluded that we should consider thalidomide-induced interstitial pneumonitis in cases with multiple myeloma following thalidomide treatment.