After the October Revolution, Valentinov left the Menshevik party. He was appointed as a 'non-party specialist' to the Supreme Economic Council of Soviet Russia (Vesenkha), and was one of the architects of the New Economic Policy (NEP) after the Russian Civil War. He also founded the journal "Torgovo-Promyshlennaya Gazeta" ("Commercial-Industrial Gazette"). During those years he collaborated closely with Nikolai Bukharin.