Ignacy Erazm Działyński (1754–1797) was a Polish nobleman (szlachcic) of Ogończyk coat of arms and a military officer, known for his participation in the Warsaw Uprising of 1794.
Born in 1754 in Konarzewo near Poznań, he was the son of the Voivode of Kalisz Augustyn Radomiecki and his wife Anna.
Educated in the Jesuit school in Poznań and the Collegium Nobilium in Warsaw, in 1784 he married Szczęsna Woroniczówna, daughter of a Spaniard of Bełsk and owner of much land in Wołyń.
He was a deputy for the famous Sejm Wielki, where together with Jan Kiliński he was one of the leaders of the 'moderate' faction, supporting the King Stanisław August Poniatowski, Polish Constitution of 3 May 1791, and advocating strengthening of the army, enfranchisement of the burghers and alliance with Revolutionary France.
He was preparing for the Uprising since 1793, and he continued his opposition to the Russians invasion and partitions of Poland by organising resistance in Wołyń until he was arrested in 1794 and sentenced to exile to Berezowo in Siberia.