The 2009 American Recovery and Reinvestment Act spurred adoption of electronic health records (EHRs) in the United States, through such measures as financial incentives to providers through Medicare and Medicaid and regional extension centers, which provide ongoing technical assistance to practices. Yet the relationship between EHR adoption and quality of care remains poorly understood. We evaluated the early effects on quality of the Primary Care Information Project, which provides subsidized EHRs and technical assistance to primary care practices in underserved neighborhoods in New York City, using the regional extension center model. We found that just general participation in, or exposure to, the project was not enough to improve quality of care. It took sustained exposure on the part of these practices and technical assistance to them before they demonstrated improvement on measures of care most likely to be affected by the use of electronic health records, such as cancer screenings and care for patients with diabetes. Participating in the Primary Care Information Project for nine or more months was associated with significantly improved quality, but only for this limited group of quality measures and only for physicians receiving extensive technical assistance.