This guidance provides information for industry, researchers, physicians, institutional review boards (IRBs), and patients about the implementation of FDA’s regulations on expanded access to investigational drugs for treatment use under an investigational new drug application (IND) (21 CFR part 312, subpart I), which went into effect on October 13, 2009. Since 2009, FDA has received a number of questions concerning implementation of the regulations. As a result, FDA is providing guidance in a question and answer format, addressing the most frequently asked questions. In a separate guidance, FDA provides answers to questions concerning the implementation of the regulation on charging for investigational drugs under an IND (21 CFR 312.8). Also in a separate guidance, FDA describes Form FDA 3926 (Individual Patient Expanded Access—Investigational New Drug Application (IND)) and the process for submitting expanded access requests for individual patient INDs.