Panitumumab is a human monoclonal antibody against epidermal growth factor receptor (EGFR), which was approved for advanced or recurrent KRAS wild-type colorectal carcinoma. Two of 11 patients who received panitumumab-containing chemotherapy in our hospital developed interstitial lung disease (ILD), and these onsets were supposed to be associated with panitumumab. Case 1, a 79-year-old man: After two courses of panitumumab and FOLFIRI therapy for recurrent colon cancer, he developed ILD and recovered by steroid pulse therapy after discontinuation of the drug. Case 2, a 76-year-old man: After seven courses of panitumumab and FOLFOX therapy as postoperative adjuvant chemotherapy, he developed ILD. Although he had steroid pulse therapy, cyclophosphamide pulse therapy, and direct hemoperfusion using a polymyxin B immobilized fiber column (PMX-DHP) therapy, he died 22 days after admission. Autopsy findings showed a pattern of diffuse alveolar damage. Panitumumab may cause life-threatening ILD; therefore we must recognize and pay careful attention to this potential pulmonary toxicity.