Cetuximab is a monoclonal antibody that treats malignant disease by inhibiting epidermal growth factor receptor. Many common adverse events have been reported and include skin rashes, infusion reactions, gastrointestinal complaints and headache. Up to now, cetuximab-associated pulmonary toxicity has been rarely reported in the literature. The present report describes two cases with probable interstitial pneumonitis 5–6 weeks after commencing treatment with chemotherapy combined with cetuximab. One patient recovered and the second patient died due to gastrointestinal bleeding 3 weeks after an initial response to steroids.