John Young (65) and his wheelchair-bound wife Angela (63) both face jail in the next week.
Mr Young, who is awaiting a hip replacement, said the first he heard about the problem was a final notice letter two weeks ago.
He now faces up to 30 days in jail, while Angela could spend 12 days behind bars, if they don't pay a fine of €1,200.
"I get €207 per week pension and Angela gets €188 long-term sickness benefit," he told the Herald.
"There's not a chance we can come up with the €1,200. If I had the money, I'd pay it."
John requires a crutch to get around, while Angela, a diabetic, is confined to a wheelchair.
John is expecting the gardai to come on Friday or next Monday to take them to Mountjoy Prison.
"I'm very frightened by it," he said. "I've never been in trouble before in my life.
"We've been together for 42 years. We're never apart really. The thought of one of us going to prison is upsetting enough, without both of us going."
John admits to not having a TV licence in the periods mentioned in the notice, but says the final notice was the first he can recall getting.
In 2012, 272 people were jailed for non-payment of TV licence fines, according to the Irish Prison Service.
This is up from 183 in 2011 and 49 in 2008.