A 69-year-old man was diagnosed with adenocarcinoma of the lung in June 2012. He had participated in the trial with informed consent, and he has been treated with bevacizumab beyond disease progression. Bevacizumab and erlotinib were administered from March 18, 2013, as the third-line treatment. Although he had no symptoms, chest X-ray revealed presence of free air in the abdominal cavity on the day of administration of the third-cycle of bevacizumab and erlotinib. An abdominal CT scan showed a small amount of pneumoperitoneum and pneumatosis in the wall of the assending colon. We diagnosed him as pneumatosis intestinalis, and both bevacizumab and erlotinib were discontinued. He was treated conservatively without surgery, and gradually pneumatosis resolved. Recent reports showed that pneumatosis intestinalis developed in some patients receiving molecular-targeted therapy. To our knowledge, this is the first reported case of pneumatosis intestinalis in a patient treated with bevacizumab and erlotinib. We are concerned that pneumatosis intestinalis would increase along with an increase in the treatment with bevacizumab.