Mr Sanders made the comments while appearing on Bill Maher's show on Friday night.
He said that while the Democrats' primary goal is to urge voters to overwhelmingly support Democratic presidential candidate Joe Biden and make a challenge to the results of the 2020 US election moot, there are plans in place should Mr Trump lose but refuse to leave the White House.
“The bottom line is, there are things that we have to do now to make sure that Biden wins. And if Trump attempts to stay in office after losing, there will be a number of plans out there to make sure that he is evicted from office," Mr Sanders said. "But right now, in the next five weeks, our job is to defeat him and defeat him badly."
Democrats have been sounding the alarm since a number of reports emerged earlier this week in which officials in the Trump administration warned that the president was examining a number of ways to stay in office in the event of an election loss.
The president himself has done little to dismiss the reports, as he has refused to commit to accept the election results on numerous occasions when pressed by reporters.
“We’re going to have to see what happens, you know, but I’ve been complaining very strongly about the ballots. The ballots are a disaster,” Mr Trump told reporters at a White House briefing Wednesday.
He went on to insinuate that he wanted to discount numerous ballots that have already been cast through early voting.
“Get rid of the ballots and you’ll have a very peaceful — there won't be a transfer, frankly. There will be a continuation,” Mr Trump said. “The ballots are out of control. You know it, and you know who knows it better than anyone else? The Democrats know it better than anyone else.”
Mr Sanders' statement Friday was not the first time he's called on Democrats to take Mr Trump's apparent threat not to adhere to the election results seriously.
"Listen to what Trump is saying," he said. "Don't brush it off."
On Thursday, Mr Sanders livestreamed a speech in which he called for all Democrats to vote for Mr Biden in massive number to defeat Mr Trump in a landslide. He said that by defeating Mr Trump with overwhelming numbers, it would make it "virtually impossible" for Mr Trump to justify staying in power.
“Never in a million years did I ever think that I would have to give a speech about what do we do if a president refuses to leave office if he loses. I never, ever thought that I would have to give that speech, or anyone else. But that is where we are today,” Mr Sanders said during his appearance on Mr Maher's show.