Lack of healthcare insurance is considered one of the drivers of the rise in emergency department (ED) use in the United States. Using survey-based, individual-level data, we compare ED use after the 2006 Massachusetts health insurance reform with ED use before the reform both in Massachusetts and nearby states. We find that the reform increased the insurance rate significantly by 5.29 percentage points. We do not find a statistically significant effect on ED visits but do not have enough power to rule out potentially relevant effects. It seems that policy makers hoping that insurance reform will dramatically decrease ED overcrowding are likely to be disappointed.