Bepridil is an antiarrhythmic drug with few reports of drug-induced lung injury. We report the case of a 73-year-old woman who had commenced treatment with oral bepridil 4 months earlier and subsequently developed cough and difficulty in breathing more than 1 month prior to presentation. Initial evaluation at our department revealed infiltrative shadows in both lung fields on chest-computed tomography. Serum KL-6 levels were 10,570U/mL. A drug-induced lymphocyte stimulation test (DLST) was negative. Bronchoscopy and bronchoalveolar lavage fluid analysis revealed 41% lymphocyte cell subpopulations. Based on a high index of suspicion of drug-induced lung injury due to bepridil, oral administration was stopped immediately, resulting in spontaneous resolution of symptoms. A repeat DLST performed 1 year after drug discontinuation was positive. We report this as a rare case of spontaneous resolution of symptoms in which DLST became positive after discontinuation of the drug.