The Starobilsk agreement was a 1920 political and military alliance between the Makhnovshchina, an anarchist mass movement led by Nestor Makhno's Insurgent Army, and the Ukrainian Soviet Socialist Republic, which the Bolsheviks had established as the government of Ukraine.

The agreement was reached following the resurgence of the White movement in Ukraine, which forced the warring Bolshevik and Makhnovist factions to put aside their differences and work together against their common enemy.

Following the Soviet victory over the Whites at the siege of Perekop, the Red Army attacked the Makhnovists, bringing an end to the agreement and igniting a conflict between the two factions that would last until the complete suppression of the Makhnovshchina in August 1921.

[1] Following the 1919 Soviet invasion of Ukraine, the Ukrainian anarchist insurgents led by Nestor Makhno integrated themselves into the Red Army, but eventually mutinied due to political and military disagreements.

[7] By August 1920, a series of defeats in the Polish–Soviet War had forced the Bolsheviks to begin peace negotiations, while Wrangel had himself launched a devastating offensive against the 13th Red Army positions in left-bank Ukraine, extending the White lines as far as Katerynoslav, Mariupol and the Don.

[17] On 6 October, the provisional agreement was signed by Andri Ivanov, Semen Karetnyk, Dmitry Popov and Viktor Bilash, with the armistice between the two factions entering into force the following day.

[18] They then arranged for the final draft of the political-military agreement to be drawn up in the Ukrainian Soviet capital of Kharkiv, where the insurgents would be represented by Dmitry Popov, Abram Budanov and Vasyl Kurylenko.

[24] On 13 October, Makhno reaffirmed in an editorial that the insurgent movement did not recognise the authority of the Ukrainian SSR and refused political collaboration with the Bolsheviks, considering the pact to be a wholly military endeavor.

[26] This fourth clause would have extended full autonomy to the Makhnovshchina, allowing them to establish institutions of workers' self-management and self-government in south-eastern Ukraine, under a federative agreement with the Ukrainian SSR.

[34] The insurgents were also unaware of the peace negotiations in Riga, which had already enforced an armistice between the Polish and Soviet forces, and underestimated the Red Army's capacity on the Southern Front.

[36] The outcomes of the pact were immediate, seeing the release of the insurgent commanders Petro Havrylenko and Oleksiy Chubenko,[37] as well as the leading anarchist intellectual Volin, from the prisons of the Cheka.

[46] An insurgent expeditionary force, commanded by Semen Karetnyk with Petro Havrylenko as chief of staff, immediately set out from Huliaipole and captured Oleksandrivsk on 23 October.

[51] The decisive end of the Northern Taurida Operation saw the Whites suffer heavy casualties and lose a substantial amount of their equipment, reducing them to a fraction of their former strength.

[52] Within only two weeks, Karetnyk's insurgent detachment had beaten back the Whites, almost completely independently of the supporting Red Army infantry and entirely without the anticipation of the Bolshevik command.

[56] Up against heavy fortifications and with their Azov flotilla indisposed,[57] the Red command concluded it would be necessary to force the Syvash, between Perekop and Chonhar, which had been made fordable by unusually strong winds.

[79] On the day that Sevastopol was captured, Karetnyk informed Makhno of their victory over telegram, to which the insurgent chief-of-staff Hryhory Vasylivsky responded by declaring the end of the Starobilsk agreement and predicting a Bolshevik attack within the week.

[81] On the night of 26 November, the Red Army launched a coordinated offensive against the Makhnovshchina: Karetnyk and the insurgent staff were ambushed and executed,[82] Huliaipole was surrounded and captured,[83] and the anarchists in Kharkiv were rounded up and arrested.

[84] The subsequent conflict between the Makhnovists and Bolsheviks lasted until August 1921, when the Makhnovshchina was decisively defeated by the Red Army and the Ukrainian Soviet Socialist Republic was established as the sole authority in the country.