Two patients developed bepridil-induced interstitial pneumonia during treatment of arrhythmia. The first patient was a 69-year-old man who received bepridil to maintain sinus rhythm in atrial fibrillation and who developed dyspnea on the 20th day after administration. The second patient was a 72-year-old man who received bepridil for paroxysmal atrial fibrillation and who developed dyspnea on the 60th day after administration. They were diagnosed with interstitial pneumonia on the basis of physical and imaging findings. The first patient was discharged after steroid pulse therapy, and the second patient after improvement of physical and imaging findings when bepridil was discontinued. Although a limited number of cases of bepridil-induced interstitial pneumonia have been reported, the disorder should be kept in mind as an important adverse reaction when breathlessness or dyspnea develops during administration of the drug.