The document profiles four health information exchange (HIE) efforts that are succeeding in getting doctors to share patient data. It discusses how HIEs enable doctors to access test results, diagnoses, and other patient information across organizations. It then summarizes four specific HIE initiatives: the Louisiana Rural Health Information Exchange which serves a rural, underserved region; state-level exchanges being developed in several states using federal funding; HealthBridge serving the Cincinnati area; and the Chesapeake Regional Information System for Our Patients on Maryland's Eastern Shore. The document concludes by noting the growth in HIEs and expectations that new federal incentives and requirements will further drive their adoption.