BACKGROUND: Concerns exist about the ability of safety net health care organizations to participate in US health care reform. Primary care practices are key to several efforts, but little is known about how capabilities of primary care practices serving a high share of disadvantaged patients compare to other practices. OBJECTIVE: To assess capabilities around access to and quality of care among primary care practices serving a high share of Medicaid and uninsured patients compared to practices serving a low share of these patients. DESIGN: We analyzed data from the National Survey of Healthcare Organizations and Systems (response rate 46.8%), conducted 2017-2018. PARTICIPANTS: A total of 2190 medical practices with at least three adult primary care physicians. MAIN MEASURES: Our key exposures are payer mix and federally qualified health center (FQHC) designation. We classified practices as safety net if they reported a combined total of at least 25% of annual revenue from uninsured or Medicaid patients; we then further classified safety net practices into those that identified as an FQHC and those that did not. KEY RESULTS: FQHCs were more likely than other safety net practices and non-safety net practices to offer early or late appointments (79%, 55%, 62%; p=0.001) and weekend appointments (56%, 39%, 42%; p=0.03). FQHCs more often provided medication-assisted treatment for opioid use disorders (43%, 27%, 25%; p=0.004) and behavioral health services (82%, 50%, 36%; p<0.001). FQHCs were more likely to screen patients for social and financial needs. However, FQHCs and other safety net providers had more limited electronic health record (EHR) capabilities (61%, 71%, 80%; p<0.001). CONCLUSION: FQHCs were more likely than other types of primary care practices (both safety net practices and other practices) to possess capabilities related to access and quality. However, safety net practices were less likely than non-safety net practices to possess health information technology capabilities.