The 21st Century Cures Act encourages the Food and Drug Administration to consider "real-world evidence" in its regulation of the safety and efficacy of drugs and devices. Many have interpreted this mandate to focus on non-randomized observational research. However, we suggest that regulatory science must also move from rarefied academic hospitals to community-based settings, where the vast majority of patients in fact receive care in the fragmented U.S. healthcare system. This move is especially important if innovations are to reach, and be validated in, more diverse populations. A solution can be found in the 183 Practiced-Based Research Networks ("PBRN"), i.e., groups of primary care clinicians and practices in all 50 states working to improve clinical care and translate research findings into practice. This symposium contribution seeks to (1) describe some of the common shortcomings of clinical trials, (2) explore the opportunities and challenges posed by use of real-world evidence as a basis for drug and device regulation, (3) briefly describe the history and evolution of PBRNs, and (4) articulate the challenges and opportunities for using PBRNs to fulfill the 21st Century Cures Act mandate for real-world evidence.