Background: Federally qualified health centers have aligned clinical services and systems with local hospitals, but little is known about the specific care integration strategies health centers use or their impact on care. We examined the use of strategies by health centers to integrate care with hospitals and emergency departments (EDs) and their association with performance on measures of health center-hospital communication. Methods: We administered a web-based survey to health center medical directors in 12 states and Washington, DC in 2017. The survey collected ten self-reported measures of communication between health centers and hospitals/EDs and the extent to which health centers used different strategies to improve care integration. We examined health center and market characteristics that predict higher vs. lower integration activity and used logistic regression to assess the relationship between integration activity and communication. Results: Between 56 and 81 percent of health centers participated in quality improvement projects, health promotion initiatives, guideline alignment, or executive meetings with hospitals; far fewer established notification agreements regarding hospital/ED utilization. Health centers that were larger, were located in rural areas or states with Medicaid accountable care programs, reported fewer staff shortages, and had fewer minority patients were associated with greater integration activity. Higher levels of integration activity were associated with better performance on most communication measures in both inpatient and ED settings (p < 0.05). Integration activity was not associated with health centers' receipt of notifications after patients' ED visits.