A veteran leader of the Mexican left has announced he is planning to run for presidency of the country in 2006, his fourth bid.
Mr Cardenas is believed to have lost the 1988 election due to fraud
Seventy-year-old Cuauhtemoc Cardenas is the founder of the Democratic Revolution Party or PRD.
Many Mexicans believe he lost the 1988 presidential elections due to widespread fraud.
But the capital's popular mayor, Andres Manuel Lopez Obrador, is also hoping to obtain the party's nomination.
Fourth time lucky?
"I am confident that I will be candidate and, when the time comes, I will have the trust of the majority," he told hundreds of gathered supporters in the capital as he launched his bid.
He pledged to bring an end to the conservative, free-market politics of the government of Vicente Fox.
"Mexico will not continue to be the prostrate and plundered country that neo-liberalism and those who serve it want it to be," he said.
Mr Cardenas' father, Lazaro Cardenas was the country's president between 1934 and 1940 and is highly regarded for having nationalised Mexico's oil industry.
Mr Cardenas had been the governor of Michoacan state before deciding to make his first bid for presidency.
He became Mexico City's first elected mayor in seven decades in 1997, a position now held by his rival Mr Lopez.