Clinical investigators invoke a number of specific regulatory requirements if their study includes use of a pharmaceutical agent. Studies using a drug that has not been approved by the Food and Drug Administration (FDA) or for indications not in the approved labeling may require filing an Investigational New Drug (IND) application with the FDA. If a study meets specific regulatory exemption criteria, then an IND may not be needed. Individual investigators may meet the FDA definition of a sponsor-investigator, in which case the application process is generally less complicated than for commercial sponsors, and this review addresses only this circumstance. Filing an IND requires completion of 3 sets of forms: 1 detailing the study (FDA Form 1571), 1 providing information about the investigator and study site (FDA Form 1572), and 1 certifying that the study is registered in the national database of clinical trials (FDA Form 3674). If the IND is approved, the study may begin 30 days after the FDA acknowledges receipt and assigns an IND. If the FDA requires additional information or if the study is placed on a "clinical hold," the study must not proceed. While the IND is active, the investigator must also continue to meet a set of regulations for monitoring the study and reporting to the FDA.