The development of molecularly targeted agents has been a key factor in recent advances in cancer therapy, and some of these agents are now considered standard therapies for various types of carcinoma. The toxicity of many of these agents is different from that of other kinds of antitumor agents. Little was known about drug-induced interstitial lung disease (ILD) when acute ILD-type events developed in several Japanese patients treated with gefitinib. A better understanding of drug-induced ILD is required, including more reliable data about the incidence of events associated with different treatments and identification of the risk factors for this type of ILD. Recent advances in imaging, molecular examination, and pathology have been used in postmarketing surveillance studies designed and conducted by an independent academic team to define the risk and to increase the amount of evidence about ILD related to various molecularly targeted anticancer agents. These studies may shed light on the underlying mechanisms of drug-induced ILD and appropriate evidence-based strategies that can be used to prevent or manage these events. At this time, the information about ILD by these molecularly targeted agents has accumulated. The guideline of drug-induced ILD will be revised by Japanese Respiratory Society based on these information. We like to discuss about new guideline.