The gauntlet was thrown down after Delaney found some common ground with Sanders after the senator criticized the DNC's debate format, which he described as "demeaning" due to the time constraints.
“Although Senator Sanders and I think about politics very differently, I do agree that the current debate format makes it hard to have an in-depth, fact-based discussion," he said in a press release Thursday.
"You can't talk about an issue like health care in 30-second clips and do it justice. Senator, I'll debate you on health care anywhere you want, long-form format. The two of us are driving the discussion across the party on the best way to achieve universal health care. Let's get in-depth and talk about the facts."
It is unclear whether Sanders has accepted or rejected the challenge. The Sanders campaign did not immediately respond to Fox News for comment.
Delaney has been an outspoken critic of Sanders' signature legislation Medicare-for-all and had a fiery exchange with him during the most recent Democratic debate. After Delaney previously described Medicare-for-all as "political suicide," Sanders shot back, telling the former congressman, "You're wrong."
"If you want stability in the health care system which gives you freedom of choice with regard to doctor or hospital, which is a system that will not bankrupt you, the answer is to get rid of the profiteering of the drug companies and the insurance companies and move to Medicare-for-all," Sanders argued.
"What I'm talking about is really simple... We should deal with the tragedy of being uninsured and give everyone healthcare as a right," Delaney later responded. "But why do we got to be the party of taking something away from people? That's what they're running on."
During his appearance on The Joe Rogan Experience" earlier this week, Sanders was asked if he gets frustrated by the "time constraints" of the debates, to which he responded, "absolutely."
"You shouldn't even call them a debate. What they are is a reality TV show in which you have to come up with a soundbite and all that stuff,” Sanders said. “It’s demeaning to the candidates and it’s demeaning to the American people. You can’t explain the complexity of health care in America in 45 seconds, nobody can."