The proposal was made by the authorities of the two regions - the Chita Region and the Aginsk Buryat Autonomous Area.
Referendums on unifying the regions, near Lake Baikal, into the Zabaikalsky Territory, will be held in March 2007. If voters back the move, the new territory will be formally established on March 1, 2008.
In early 2008, the local legislatures will vote on a new president-appointed governor. Elections to the new region's legislature will be held in October 2008.
The unification, one of a series of similar moves in Russia recently, is expected to provide an economic boost and to raise local living standards.
The Perm Territory in the Urals was formed from the Perm Region and the Komi-Permyak Autonomous Area, comprising more than 160,000 square kilometers, uniting a population of about 3 million, on December 1, 2005.
The Krasnoyarsk Territory will be expanded to include the Taimyr (Dolgano-Nenets) and the Evenki autonomous areas, all in Central Siberia, in January 1 next year. The new territory will have a population of more than 3 million.
The Irkutsk Region in east Siberia will absorb the Ust-Ordyn Buryat Autonomous Area on January 1, 2008, following an approval by referendum in April.
Preparations are also underway to unify Krasnodar Territory and the Republic of Adygeya in southern Russia.