Amiodarone, a highly effective medication for suppressing cardiac rhythm disturbances, may cause pulmonary injury, such as chronic interstitial lung diseases, in 5–15% of the patients who take it. We applied induced sputum (IS), a non-invasive technique, for diagnosing amiodarone-induced pulmonary toxicity. Four patients with interstitial lung disease who were treated by amiodarone for ischemic heart diseases were evaluated by a conventional clinical workup. All four patients showed marked interstitial pattern on computerized tomography and decreased diffusion capacity (DLCO-SB 51–76%). IS showed lymphocytosis, a high CD4 or CD8 count, eosinophilia and amiodarone in 3 of 4 patients. IS may be a useful tool for assessing amiodarone toxicity in patients with ischemic heart diseases and concomitant pulmonary side effects.