The presenter revealed on his blog that the decision was made to allow public television stations to plan their schedules in 2012.
He added that the show also needs to find an additional source of financial help, as he and wife Chaz Ebert have been funding the programme entirely themselves.
"We held off as long as possible but we had to give notice today," he wrote, adding that it was "a sad but necessary moment of realism".
Ebert explained that they had recently spoken with web services, charities, corporate sponsors and executives for potential sources of funding.
"We are still talking with them, but the time crunch has intervened," he said. "So we are going on hiatus while we sort it out."
At the Movies is the current form of Ebert's 1979 show Sneak Previews, which he launched with Gene Siskel.
Roger Ebert completed a series of surgeries in 2010 which left him with no lower jaw or salivary glands after losing them in 2006 from cancer. He has not been able to speak, eat or drink unassisted since.