The purpose of this guide is to help small businesses - usually those with fewer than 500 employees - successfully navigate the realm of regulatory measures with which he U.S. Food and Drug Administration (FDA or the Agency) protects and promotes the health of the American public. Familiarity with FDA requirements is very important for a small firm that manufactures or plans to manufacture, sell, warehouse, transport, or import any of the thousands of FDA regulated products. To reach the U.S. interstate market, these products must comply with the applicable laws and the science-based public health rules developed and enforced by FDA. Although this obligation is routinely fulfilled by hundreds of thousands of American businesses, FDA is aware that for a small firm it can present a challenge. The Agency's responsibilities are defined in some 200 federal laws, and the resulting requirements, which can be complex, cover hundreds of pages in the Code of Federal Regulations. To find their way in this extensive domain of requirements, small and start-up businesses are likely to need expert assistance. The purpose of this guide is to help satisfy this need. Chapters I-IV provide an overview of FDA's responsibilities and operations and outline the main areas where small firms are most likely to come in contact with the Agency. Chapter V provides links to information that small businesses most frequently request from FDA's product centers and the Agency's Office of Regulatory Affairs. Chapter VI lists the Agency's offices and individuals who are ready to help small firms resolve their regulatory problems. This guide is designed to help make the small firms' contacts with FDA as efficient and productive as possible. We present this document as a blueprint that firms can follow to achieve their business aims while helping FDA accomplish its public health mission.