In September 1939, Voronov commanded the Belorussian Military District's artillery during the Soviet invasion of Poland. He was severely injured in a car accident and said his life was saved by a silver pen given to him by Dolores Ibárruri in Spain. In November, Voronov inspected the troops of the Leningrad Military District, in readiness for the Winter War. During the war, he led artillery units, mainly those of the 7th Army, and fought in the offensive against the Mannerheim Line. For his actions during the war, Voronov was awarded a second Order of Lenin and was promoted to Komandarm 2nd rank. On 4 June 1940, he was given the rank of colonel general of the artillery after the introduction of Red Army general officers ranks. Voronov led the Kiev Special Military District's artillery during the Soviet occupation of Bessarabia and Northern Bukovina.