Officials had conditionally approved the plans of 11 other states and the District of Columbia before this week.
HHS Secretary Kathleen SebeliusKathleen SebeliusObama's health secretary to be first female president of American University Leaked email: Podesta pushed Tom Steyer for Obama’s Cabinet Romney: Trump victory 'very possible' MORE praised states' progress.
"States across the country are working to implement the health care law and build a marketplace that works for their residents," Sebelius said in a statement.
“In ten months, consumers in all fifty states will have access to a new marketplace where they will be able to easily purchase affordable, high quality health insurance plans."
Exchanges must be up and running by 2014, but many Republican governors have refused to move forward, ceding the task of establishing the marketplaces to the federal government.
On a conference call with reporters, HHS officials said that Utah — a special case because it already runs a health exchange — will have to make adjustments in order to fully comply with the Affordable Care Act.
Specifically, the state will have to expand its marketplace to offer coverage for individuals, not just small businesses as the exchange does now.
A confrontation between Utah and federal officials has been brewing for months over the exchange.
Ally Isom, deputy chief of staff to Utah Gov. Gary Herbert (R ), released a statement saying that the state would not agree to making major changes to its health exchange.
"Utah’s position on our state health exchange has not changed and it will not change. Because it’s consumer-driven, market-based and flexible, Utah’s model is the right solution for Utah," Isom said.
"Of course we’ll review the HHS announcement and determine if the conditions are acceptable or reasonable for our state exchange … but there is nothing about Utah’s path that changes as a result of today’s announcement."
—This post was updated at 4:54 p.m.