Russia and Poland concluded a $2.5bn (£1.6bn) deal over the weekend to construct a pipeline through which natural gas supplies from Siberia will be pumped to Western Europe by early next century.
The deal, the most important of several signed by Russian Prime Minister Viktor Chernomyrdin during a long-awaited visit to Warsaw, was the largest between the two countries since the collapse of the Moscow-led Comecon trading bloc in 1990.
It also underlined the fact that, despite political friction, both are keen to revive economic ties.
At Saturday's signing ceremony, Mr Chernomyrdin said the pipeline, which will run from Yamal in Siberia to the German-Polish border, was of great importance not only for Russia and Poland, but for all of Western Europe.
The pipeline is due to come on stream by the beginning of the next century. On completion, it will be able to transport some 67 billion cubic metres of Siberian gas per year, up to 14 billion cubic metres of which could be distributed within Poland itself.
Moscow and Warsaw originally reached agreement on the construction of the Polish section of the pipeline in August 1993.
Covering 650 kilometres, the cost of the project was set at $2.5bn. The final signing was delayed partly because of continuing political tension, focused around Moscow's disapproval of Warsaw's determination to join the Nato military alliance.
Mr Chernomyrdin's visit was originally scheduled for last November but was cancelled at the last minute.
After a dramatic slump in trade following the collapse of Comecon, economic ties between Poland and Russia and the former Soviet republics - once worth some $12bn a year - last year showed the first signs of recovery, rising from $2.9bn in 1993 to $3.4bn.
Commenting on Mr Chernomyrdin's visit to Poland, the Polish daily newspaper Rzeczpospolita said the two countries, which recently agreed to cancel mutual debts dating back to Comecon days, seemed able to agree on economics far more easily than on politics.
"Trade brings nations closer," the newspaper said, adding that the two countries were now well on the way to establishing good "partner-like" relations to replace the formerly subordinate role Poland played to Moscow during the communist era.