"We have reached the conclusion that it is in our interest to limit to a maximum of two consecutive five-year terms service in top state and political roles," Castro, 79, told the 1,000 delegates as he opened the Communist Party Congress.
"This is possible and necessary in our current situation," added the 79-year-old, who took over from Fidel Castro during his brother's health crisis back in 2006.
It was not immediately clear if, or how, Raul Castro meant for the measure to apply to himself as president. He turns 80 in June. And Raul Castro lamented that, in his view, there were no younger Cubans ready to take over the helm of the party and the nation immediately.
"Today, we face the consequences of not having a back bench of adequately prepared replacements, who have enough experience and maturity to take on the new and complex duties of managing the party, state and government," he told delegates.
The president said, without elaborating, that glory-seeking by unnamed parties could stand in the way of the Communist Party being "worthy of the unlimited support of the people and the revolution, for all time."
Delegates of the meeting will, over four days, vote on economic reforms proposed by Castro and officially relieve his ailing 84-year-old brother as party leader. It was the sixth Communist Party Congress convened by the only one-party Communist regime in the Americas, and the nation's first in 14 years.
"The confidence and the united majority of Cubans have been tested, with regard to the party and the revolution," Castro acknowledged on opening the gathering. "It is a unity that is not without differences of opinion."
Fidel Castro, who has led the party since its founding in 1965, announced three weeks ago he had resigned the party leadership when he first took ill. He is widely expected to pass that mantle to Raul officially.
The congress will elect a new 100-member Central Committee, as well as the more elite 19-member Politburo and 10-member Secretariat. The government has said the congress will formally enshrine many economic reforms the government has adopted over the past year. Reforms are desperately awaited in a country where the average salary is $17 a month, domestic food production is a problem and corruption widespread.