Brenda Martin, 51, made the appeal on the Canadian CTV television network by telephone, asking Prime Minister Stephen Harper to help.
"I'd like to plead for my life to the prime minister of Canada to please pick up the phone and call the president of Mexico and have this travesty ended," she said. "Please help me, prime minister, please help me, please help me. I don't know how to get through a day here."
Martin was a chef for Alyn Richard Waage, who was arrested in 2001 and jailed for investment fraud. Five years later, Martin was picked up and detained, although she hasn't been charged with anything, CTV said.
Earlier this week, former Prime Minister Paul Martin visited the woman during an unrelated trip to Mexico. He reportedly talked with prison officials to ask for better conditions for her, as she shares a 9-by-12 foot cell with 11 women.
"Eight of them sleep on the floor so you have to crawl over their heads to get to an outhouse bathroom," she said.