This workshop will engage program directors of the NSF Research Experience for Undergraduates (REU) Sites program in discussions on the implementation of the REU Site program. The REU Site program provides opportunities for undergraduate students from across the country to conduct research in an area of their interest and to develop their skills to become leaders in a STEM field. The REU program provides opportunities for students, especially those coming from schools with limited research activity or those from underrepresented groups, to learn about how research is conducted and to understand the scientific basis of their research. Students train under the mentorship of selected faculty, learn state-of-the-art lab techniques and instrumentation, and acquire quantitative skills that prepare them for a future career in STEM. The development and training of undergraduates is vital to a robust U.S. economy and to maintaining continued global competitiveness in science and technology.<br/><br/>The Rocky Mountain Biological Laboratory will organize the workshop which will be held in September 2021. The goal is to provide a venue for REU Site program directors to share best practices on implementing an REU program and to discuss important issues associated with undergraduate research training. Program directors funded by the Division of Biological Infrastructure will meet for three days to discuss many topics, such as ways in which student identity as a scientist can be enhanced, effective communication of science, and issues on gender and ethnic/racial diversity, responsible conduct of research, effective mentoring, recruitment and selection of students, and careers in STEM. A report that captures the discussions will be posted at www.bioreu.org website and disseminated to the REU community.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.