HRSA supported health centers have a long history of participating in ambulatory care accreditation; however, there is a dearth of information on the relationship between accreditation and quality of care. We conducted a cross-sectional study of 1,202 health centers, using multivariate regression to estimate the association between accreditation and 14 clinical quality measures, controlling for patient and organizational characteristics. We also predicted national estimates of accreditation-related improvement in quality. Adjusted analyses show that accredited health centers achieved higher performance on adult weight screening and follow-up (coef = 0.037, p < .05), tobacco cessation intervention (coef = 0.042, p < .05), and use of lipid-lowering therapy (coef = 0.028, p < .05). Study results show that universal accreditation could result in additional 552,087 adult patients receiving weight screening and follow-up, 157,434 receiving tobacco cessation intervention and 25,289 receiving lipid-lowering therapy. This is the first national study to examine the impact of accreditation on health center quality of care. Findings suggest that HRSA support for accreditation has the potential to improve quality of care and as a result, reduce health disparities in underserved communities across the United States. Further research is necessary to identify specific elements of accreditation that have the greatest impact on quality of care.