As police removed them, the protesters, many with disabilities, chanted they'd "rather go to jail than die without Medicaid," according to CNN affiliate KMGH-TV.
The protesters had arrived Tuesday morning, according to a statement from the senator's office. They urged Gardner to vote against the Senate's health care legislation.
"We asked security and police to not remove these individuals from the office," Gardner's office said in a statement. "We had staff spend the night in the office on Tuesday and Wednesday nights to prevent security or police from removing them from the office and took several other significant steps to ensure they were comfortable and safe."
But Thursday, police received a request to remove the protesters through a signed complaint from the senator's office, said Marika Putnam, public information officer for the Denver police.
The 10 were arrested when they didn't disperse, she said. The charges against the protesters vary and will be announced Friday, Putnam told CNN.
The protesters were removed "due to several factors including concerns for their health and safety, and the impact of the protest on other tenants in the building," according to the statement from Gardner's office.
The senator had met with the group on an earlier occasion, according to his office. Gardner's health care policy staffer has had meetings or phone calls with people from the group 16 times since January, according to his office's statement.
One participant posted a Facebook Live video as officers came to remove them. The protesters raised their fists and lay on the ground. They chanted, "Shame on Gardner. Shame on you."
Many of the protesters came from ADAPT, a disability rights organization, KMGH reported.
Last week, ADAPT had organized a "die-in" protest outside Senate Majority Leader Mitch McConnell's office
over the health care bill. Many of the protesters, who use wheelchairs, lay on the floor protesting the Medicaid cuts.
Medicaid covers more than 70 million low-income children, parents, elderly and disabled Americans.
The Senate bill would radically overhaul Medicaid,
effectively ending Medicaid expansion and greatly reducing federal support for the overall program.