Viktor Stepanovich Chernomyrdin (, ; 9 April 19383 November 2010) was a Russian politician. He was the first chairman of the Gazprom energy company and the longest-serving Prime Minister of Russia (1992–1998). He was a key figure in Russian politics in the 1990s, and a participant in the Russian transition from a planned to a market economy. From 2001 to 2009, he was Russia's ambassador to Ukraine. After that he was designated as a presidential adviser.