Rival political leaders have signed a deal they hope will reunite Somalia after 15 years of division.
Under the agreement, the transitional parliament will assemble in the next 30 days for the first time on Somali soil.
The parliament includes representatives of the main clans and militia groups and last met in Kenya a year ago.
The Yemen talks have been led by the president who is based outside the capital and the parliamentary speaker allied to militias who run Mogadishu.
The head of the BBC Somali service, Yusuf Garaad Omar, says this is a major breakthrough for the peace process, which has stagnated since the transitional government was sworn in more than a year ago.
Funding threat
However, there is no mention in the agreement about where the parliament will be based.
President Abdullahi Yusuf has previously refused to move to Mogadishu on security grounds, because it is controlled by rival militias and had set up his government in the town of Jowhar - some 90 km away.
But Speaker Sharif Hassan Sheikh Adan and many MPs disagreed and went to the capital to try and establish a rival administration.
It is unclear where the parliament will meet.
A Yemeni official close to the talks told Reuters news agency that the leaders had deliberately omitted the location of the government to avoid angering warlords. "In principle, they agreed that the government will first move to Baidoa and then Mogadishu," the official said.
The five-part agreement also calls for respect for the constitution under which Somalia's failed central government and parliament was established in 2004.
It calls for all groups to put aside their differences to unite the government and the country.
But it does not say when, or even if, President Yusuf should move the central government back to Mogadishu.
The international community had made it very clear it would not fund the new government if it remained divided.
Correspondents say Mr Yusuf's eventual return to the capital is likely to depend on an agreement by the militias to withdraw from the streets of Mogadishu.
The country has been controlled by rival militias since 1991 and has become one of the poorest countries in the world.
An interim administration was elected by parliament when it met in Kenya in late 2004.