The documents were signed by the respective prime ministers of the three Eurasian Economic Community countries at a meeting of the Eurasec Interstate Council under a plan to establish the Customs Union by 2010.
Other members of Eurasec, an international economic organization, Tajikistan, Uzbekistan and Kyrgyzstan will be able to join the union at a later date as they become ready.
The package of nine documents outline joint customs regulations, third party rules, tariffs for duty on goods from third countries and other procedures which complete the legal basis for the union.
"I consider the signing of the package of agreements... by Russia, Belarus, and Kazakhstan the most important outcome of the meeting," Russia's prime minister said after the council meeting.
"No doubt further efforts will lead us to the goal of creating a Eurasec common economic space," Viktor Zubkov said.
"We will also try to join the customs space, I mean Tajikistan, Kyrgyzstan, and Uzbekistan," Tajikistan's prime minister said.
Akil Akilov also said the participants in the meeting suggested focusing on the agricultural sector and working out a Eurasec food security model.
In October 2007, the three countries signed the creation plan and the first package of agreements on the Customs Union, including the formation of a customs union commission, a common customs area, and the order of membership.
