The ability to generate and use registries--lists of patients with specific conditions, medications, or test results--is considered a measure of physicians' engagement with electronic health record systems and a proxy for high-quality health care. We conducted a pre-post survey of registry capability among physicians participating in the Massachusetts eHealth Collaborative, a four-year, $50 million health information technology program. Physicians who participated in the program increased their ability to generate some types of registries--specifically, for laboratory results and medication use. Our analysis also suggested that physicians who used their electronic health records more intensively were more likely to use registries, particularly in caring for patients with diabetes, compared to physicians reporting less avid use of electronic health records. This statewide project may be a viable model for regional efforts to expand health information technology and improve the quality of care.