Panitumumab, a fully-human monoclonal antibody against epidermal growth factor receptor (EGFR), is used as standard chemotherapy for patients with advanced colorectal cancer. From June 2010 to April 2011, 3 of 13 patients who received panitumumab-containing chemotherapy in our hospital developed interstitial lung disease (ILD); in all 3 we suspected a causal relationship between panitumumab and the ILD. The 3 had multiple lung metastases; 2 had a smoking history; and 1 had signs of suggestive unspecified interstitial change on a CT scan at the beginning of the panitumumab therapy. The ILD was diagnosed 54, 15, and 15 days after initiation of the panitumumab therapy, respectively. The first patient died 22 days after the diagnosis of ILD, and the second and third recovered and remain alive. The first and second patients received steroid pulse therapy after discontinuation of the drug, and the third recovered without steroid therapy. The frequency and clinical features of panitumumab-associated ILD remain to be elucidated. However, since gefitinib and erlotinib, which also target EGFR may cause serious ILD, careful monitoring of ILD is necessary in patients who receive panitumumab therapy.