Health insurance exchanges created under the Affordable Care Act will offer coverage to people who lack employer-sponsored insurance or have incomes too high to qualify for Medicaid. However, plans offered through an exchange may include high levels of cost sharing. We surveyed families participating in unsubsidized plans offered in the Massachusetts Commonwealth Health Insurance Connector Authority, an exchange created prior to the 2010 national health reform law, and found high levels of financial burden and higher-than-expected costs among some enrollees. The financial burden and unexpected costs were even more pronounced for families with greater numbers of children and for families with incomes below 400 percent of the federal poverty level. We conclude that those with lower incomes, increased health care needs, and more children will be at particular risk after they obtain coverage through exchanges in 2014. Policy makers should develop strategies to further mitigate the financial burden for enrollees who are most susceptible to encountering higher-than-expected out-of-pocket costs, such as providing cost calculators or price transparency tools.