Once completed, two pipelines will deliver Russian gas to Turkey and Europe.
Russia's upper house of parliament, the Federation Council, on Wednesday approved a bill to ratify a natural gas project that will benefit Russia, Turkey and Europe.
Russia's lower house ratified the TurkStream project on January 20. Turkey's General Assembly approved it on December 2, 2016.
The project envisages two pipelines, each with a capacity of 15.75 billion cubic metres, that will run beneath the Black Sea.
One pipeline will deliver Russian gas to Turkey, the other to Europe.
The project dates to December 2014, but was put on hold after Turkey shot down a Russian jet which violated Turkish airspace over the Turkey-Syria border in November 2015.
The two sides agreed in October 2016 to restart the project during a visit to Istanbul by Russian President Vladimir Putin.
Construction of the pipelines is expected to be completed by 2019.
Turkey is the second biggest consumer of Russian natural gas after Germany. It already imports about 30 billion cubic metres annually via two pipelines, the Blue Stream, which passes under the eastern Black Sea, and the Western Line through the Balkans.