A CBS News analysis found that in the 15 states with public health insurance exchanges, more people are enrolling in Medicaid instead of buying private health insurance.
In Kentucky, of the 26,000 people newly enrolled in healthcare, 82 percent are in Medicaid, and in New York, of 37,000 new enrollments, Medicaid accounts for 64 percent, CBS News said.
"We're seeing a huge spike in terms of Medicaid enrollments," said Matt Salo, executive director of the National Association of Medicaid Directors.
The Obama administration said that it expected a spike in Medicaid enrollments because the Affordable Care Act, or Obamacare, expands the number of low-income people who can get Medicaid.
Monday, President Barack Obama emphasized success of the healthcare law at the state-level.
"There's great demand at the state level as well. Because there are a bunch of states running their own marketplaces," Obama said.
However, Gail Wilensky, a former Medicaid director, said there need to be more healthy adults buying private health insurance for the system to work.
"Either the private insurance enrollments come up somewhere around the expected amount or there's going to be a problem. You need a volume and you need a mix of people that are healthy as well as high users in private insurance, in order to have it be sustainable," she said.