March 14 armies of the Ukrainian front started the offensive in right-bank Ukraine, unauthorized by Commander-in-chief I.I.Vatsetis. Working balances of the General Headquarters, assigned to the South front, were used for reinforcement of the front. It allowed the Ukrainian front to stop the advance of the UNR by the end of March, and then, developing its success, seize Odessa April 6 and then Crimea.
The unit of forces of the Ukrainian front was sent for help to the Hungarian Soviet Republic in April, but due to aggravation of the situation in Donbass and revolt of the 6th Ukrainian rifle division in the rear of the front the help wasn't rendered. Failure of execution of the orders of the General Headquarters of shifting armies to reinforcement of the Southern front and attempts of the Ukrainian headquarters of independent actions led to disbandment of the Ukrainian front.
During fierce battles armies of the Southern front managed to break the resistance of general Denikin's armies and in April 1919 force crossed river Manych in Velikoknyazheskaya area, starting advance to Bataisk and the Tikhoretskaya. Simultaneously armies of the front combated against insurgent Cossacks, and a unit of forces was sent for struggle against troops of N.I.Makhno, who showed distrust to the government of the USSR, kept out food brigades from the regions controlled by him and prohibited formation of the Combeds (the committees of the poor). General Denikin took the advantage of complicated situation in the rear of the Southern front. In May his troops launched a counter-offensive and forced armies of the Southern front leave the Don area, Donbass and part of Ukraine.
Reinforced in July the Southern front prepared counterattack on the 15th of August. However, headquarters of the Don army managed to get intelligence on the preparing operation. Aiming at its derangement the 4th Don cavalry corps of general K.K.Mamontov started the raid of rears of the Southern front, disorganizing the work of its supplying services and army conducting bodies, which was one of the reasons of failure of the planned counterattack.
Main bodies of the Southern front, suffering great losses, retreated to the north. September 20 the Voluntary army seized Kursk, and in the beginning of the October the Don army seized Voronezh. The TSK of the RCP (b) again interfered with conduction of the armed struggle, taking decision of reinforcement of the Southern front by means of shifting the troops from the Petrograd sector of the Western front and from the 6th detached army. The younger and energetic former colonel A.I.Yegorov was appointed the new commander of the Southern front instead of the former 50-year-old general V.N.Yegoryev.
The front was divided into - the Southern and the Southeastern (commander- V.I.Shorin) fronts. At the same time TSK took measures on bringing the Cossacks in the side of the Soviet authority. September 11 after reinforcement the Southern front launched counter-offensive. Its armies inflicted a defeat to the main body of the Voluntary army, seized Orel and on 24th - Voronezh. During further advance Kastornaya and Kursk were released. Next by the close of December armies of the South and the Southeastern front released Donbass. January 3 -Tzaritsyn, 7 - Novocherkassk, 10, 1920 - Rostov-on-Don were seized.
December 16, 1919 forces of the 12th army seized Kiev. With coming out of the Soviet armies to approaches to Northern Caucasia, the Southeastern front was renamed Caucasian, and the South - Southwestern. Its armies set free right-bank Ukraine and February 7 occupied Odessa. In January-April 1920 the Caucasian front crushed the armed forces of South Russia, coming out to the borders of the Azerbaijan and Georgian republics. April 4 general A.I.Denikin passed the command of the rest of his armies to general P.N.Vrangel, who started to raise the Russian army in Crimea.