Under the deal reached between the two companies in 2009, Gazprom would have 51 percent stake in the joint company, while Srbijagas would control 49 percent, Beta reported.
The deal was signed in the northern Serbian town Banatski Dvor, where the storage would be constructed, it added.
Dusan Bajatovic, head of the Srbijagas said all activities aimed at completing the new ownership structure of the company would be finished by March 31, Beta reported.
The value of the joint venture is estimated at about 50 million euros (69.1 million dollars) and the capacity of the future storage would be 470 million cubic meters of gas, Beta quoted Bajatovic as saying.
The storage would also serve as a part of the 20 billion-euro (30 billion dollars) South Stream pipeline should be completed by 2015 and will run under the Black Sea to Bulgaria, Serbia and Hungary before branching out to Western Europe.
The part passing through Serbia should be 450 kilometres (270 miles), with capacity of at least 20 billion cubics of gas per year. It is expected that some 700 million euros would be invested in the construction of Serbia's branch of the pipeline.
Last February, Russian giant Gazprom Neft has bought a 51-percent stake in Serbian oil monopoly NIS for 400 million euros, pledging to invest around 550 million euros in the Serbian company.
As part of a wide-ranging accord, Serbia allowed the transit across its territory of the South Stream gas pipeline while Moscow pledged to build an underground gas storage facility in Serbia.