The Food and Drug Administration (FDA) issued draft guidance on August 15, 2011 to help researchers and manufacturers design better quality clinical studies in support of premarket approval applications for certain medical devices. Although the public can comment on the draft guidance at any time, FDA has requested that interested parties submit their comments by November 14, 2011. FDA has previously articulated policies related to design of studies intended to support specific device types, and a general policy of tailoring the evidentiary burden to the regulatory requirement, but the FDA has not previously attempted to describe the different clinical study designs that may be appropriate to support a device premarket submission, or to define how a sponsor should decide which pivotal clinical study design should be used to support a submission for a particular device. The draft guidance describes different study design principles relevant to the development of medical device clinical studies that can be used to fulfill premarket clinical data requirements. The guidance applies to therapeutic and aesthetic devices and diagnostic devices. While the guidance also includes principles that are applicable to device-specific issues for combination products defined under 21 CFR Part 3 (e.g., device-drug products; device-biologic products), drug-specific or biologic-specific issues that may also be relevant for a combination product are not described. In addition, the document is not intended to provide a comprehensive tutorial on the best clinical and statistical practices for investigational medical device studies.