The pro-Kremlin United Russia party officially nominated First Deputy Prime Minister Dmitry Medvedev as its presidential candidate at its convention on Monday.
Only one out of 479 congress delegates voted against Medvedev's candidacy.
Medvedev was initially named on December 10 by the United Russia party and minor pro-Kremlin parties as a presidential candidate. His nomination was later backed by President Vladimir Putin.
On December 11, Medvedev proposed that Putin be appointed prime minister after the March 2008 presidential election.
Medvedev said that if he was elected president, he would follow the guidelines set out in Putin's plan. He did not specify or clarify the exact details of the current president's plan.
Before voting on Medvedev's candidacy, Putin told the delegates that he would agree to become Russia's prime minister if Medvedev wins the 2008 presidential election.
"If today Russians demonstrate their trust in Dmitry Medvedev, then I am ready to continue our common policy in the post of head of the Russian government," Putin said.
He also said he would work as premier without any reorganization of powers between the presidential and prime ministerial posts. However, some experts called into question Putin's assurances that there would be no redistribution of powers in favor of the prime minister.
"Presumably, during the first two years, Putin will act as a stronger political figure, protecting a younger president from possible mistakes and failures," said Vitaly Tretyakov, editor-in-chief of the Moskovskiye Novosti Russian-language weekly.
After this 'honeymoon period', he speculated, Putin and Medvedev would redefine their working relationship.
Political analyst Vyacheslav Nikonov suggested that if Medvedev was elected president and Putin became prime minister, "an effective system of checks and balances" would be created in the government.
He added that in his opinion both Putin and Medvedev would remain key figures in international affairs.
Medvedev, 42, a trained lawyer, worked under Putin in the early 1990s in the St. Petersburg mayor's office. In Moscow in 1999, he was appointed acting deputy chief of the presidential staff. Like Putin, Medvedev is a St Petersburg native.
He also headed the president's campaign headquarters in the run-up to the 2000 elections. In 2003, he became chief of the presidential administration and retained the post until November 2005, when he was appointed first deputy prime minister and put in charge of an ambitious multi-billion dollar "national project" to improve living standards.