BACKGROUND Massachusetts enacted health care reform in 2006 to expand insurance coverage and improve access to health care. The objective of our study was to compare trends in health status and the use of ambulatory health services before and after the implementation of health reform in Massachusetts relative to that in other New England states. METHODS We used a quasi-experimental design with data from the Behavioral Risk Factor Surveillance System from 2001 to 2011 to compare trends associated with health reform in Massachusetts relative to that in other New England states. We compared self-reported health and the use of preventive services using multivariate logistic regression with difference-in-differences analysis to account for temporal trends. We estimated predicted probabilities and changes in these probabilities to gauge the differential effects between Massachusetts and other New England states. Finally, we conducted subgroup analysis to assess the differential changes by income and race/ethnicity. RESULTS The sample included 345,211 adults aged eighteen to sixty-four. In comparing the periods before and after health care reform relative to those in other New England states, we found that Massachusetts residents reported greater improvements in general health (1.7%), physical health (1.3%), and mental health (1.5%). Massachusetts residents also reported significant relative increases in rates of Pap screening (2.3%), colonoscopy (5.5%), and cholesterol testing (1.4%). Adults in Massachusetts households that earned up to 300% of the federal poverty level gained more in health status than did those above that level, with differential changes ranging from 0.2% to 1.3%. Relative gains in health status were comparable among white, black, and Hispanic residents in Massachusetts. CONCLUSIONS Health care reform in Massachusetts was associated with improved health status and the greater use of some preventive services relative to those in other New England states, particularly among low-income households. These findings may stem from expanded insurance coverage as well as innovations in health care delivery that accelerated after health reform.