The Greater Plains Collaborative (GPC) is a network of 12 leading medical centers in eight states committed to a shared vision of improving healthcare delivery through ongoing learning, adoption of evidence-based practices, and active research dissemination. GPC builds on strong research programs at individual sites, existing community engagement and informatics infrastructures and data warehouses developed through the NIH Clinical and Translational Science Award (CTSA) initiative at most sites; extensive expertise with commercial EHR systems and terminology standardization; and strong working relationships between investigators and healthcare system information technology departments. This network brings together a diverse population of 16 million people across 1300 miles covering 8 states with a combined area of 679,159 square miles. GPC Clinical Data Research Network (CDRN) is part of the nationwide PCORnet, funded by the Patient-Centered Outcomes Research Institute. CDRNs aggregate electronic health record data that originate in healthcare systems such as hospitals, health plans, or practice-based networks and securely collect "real-time," "real-world" health information during the routine course of patient care. The GPC partnership will focus on studies of rare diseases, investigations of disorders requiring huge patient populations, and comparative effectiveness research.