The Collection Development Guidelines of the National Library of Medicine establish boundaries for the Library's permanent collection and provide a conceptual and philosophical framework for the selection of biomedical materials. Defining the boundaries of the NLM collection is complicated by the interdisciplinary nature of biomedicine, the prominence of political, ethical, economic and social issues in contemporary biomedical practice and research, rapid advances in health care technology and the proliferation of information sources and formats.

The Guidelines are based on the Collection Development Policy adopted by the NLM Board of Regents in 1976 and amended in 1983, 1992, and 2019. The Guidelines are intended primarily for NLM staff, but also may be of interest to a wider community of users including the staffs of other health science and research libraries, publishers and researchers. The Guidelines define the range of subjects to be acquired and the extent of the Library's collecting effort within these subjects. They also address selection issues presented by a range of formats and literature types. The Guidelines do not present principles for the selection of materials temporarily retained for the use of on-site users; nor do they describe the full range of information resources, including databases, to which NLM provides access.