In 1919 Greece participated in the campaign undertaken by the Allies in Ukraine against Soviet Russia for the overthrow of the new regime.

The Greek expedition consisted of the 1st Army Corps under the command of Major-General Constantine Nider. From the three divisions of the Corps only two were finally dispatched to Ukraine. These joined three French, one Polish and units of White Russian volunteers, the 1st Allied Group Divisions. At the same time, units of the Greek fleet joined the French and British to form a mixed naval squadron.

The Soviet government responded with three armies, which, from January 1919, after the crushing of the autonomist Ukranian movement, started moving towards the Crimaea and Odessa. The Red Army scored continuous victories against the Allied forces, the activity of which was soon limited to rearguard retreat until its final departure in the summer of 1919. The Greek army was already in Romania with the command to guard the River Dniester. It has been replaced by units of the Romanian army and left to be conveyed to Smyrna.

The participation of the Greeks in the Ukraine campaign was dictated by diplomatic reasons, in an attempt by Eleftherios Venizelos to secure the favour of the Allies towards Greek national claims. Apart from casualties, dead and injured soldiers who had taken part in the campaign, the fate of the Greek communities in Russia was tragic, as they provoked the suspicions of the Soviet regime and were eventually expelled and forced to flee as refugees to Greece.