Mr Sarkozy said both countries saw nuclear power as key for development
Italian PM Silvio Berlusconi and French President Nicolas Sarkozy have agreed that their countries will work together to revive nuclear power in Italy.
The Italian power company, ENEL, and its French counterpart, EDF, agreed a deal to study the feasibility of building four power stations in Italy.
They would replace those closed in accordance with a referendum held after the Chernobyl nuclear accident in 1986.
Since then Italy has become the world's biggest net importer of electricity.
Shortly after taking office in May, Mr Berlusconi's centre-right government announced plans to build nuclear power stations to reduce the country's dependence on foreign oil and gas.
Earlier this month, Sweden's government unveiled plans to overturn a nearly 30-year-old decision to gradually phase out nuclear power.
The Italian and French leaders signed the nuclear co-operation deal in front of TV cameras after talks in the Italian capital on Tuesday.
"We have to wake up from this sleep... and begin the construction of Italian nuclear power plants," Mr Berlusconi told reporters.
"France is making available its know-how and that will allow us to save several years and start the construction of nuclear plants in a limited amount of time," he added.
Mr Sarkozy said his country was proposing "an unlimited partnership" with Italy in the development of "clean energy".
He explained that they both wanted "nuclear power to become a European issue, because it represents the key for development".
ENEL and EDF will study the feasibility of building four EPR plants in Italy
"By 2020, nuclear plants will have to be massively developed, nobody can in any way veto that," he added.
The Italian government has said it needs eight to 10 European Pressurised Reactors (EPR), or improved third-generation plants, according to the Reuters news agency. ENEL said the first plant should be ready by 2020.
But analysts question the ability of the company to fund the construction programme, and foresee delays arising from wrangling over whether the power stations will be overseen by an independent regulator or a government agency.
The separate agreement signed on Tuesday by ENEL and EDF will see the firms study the feasibility of building four EPR plants in Italy.
It also provides for greater participation by ENEL in the French nuclear programme. The company already has a 12.5% stake in France's first EPR plant, which is being built in Flamanville in the north-west of France.