Konstanty Ireneusz Łubieński, Pomian coat of arms[1] (19 February 1825 – 16 June 1869) was a Roman Catholic bishop of the Diocese of Sejny or Augustów.

[3] On 5 August 1846, he was given a tonsure and ordained to the minor orders of porter and lector by Tadeusz Łubieński.

[4] In 1847, he begun attending the seminary at the Church of the Holy Cross in Warsaw; there, he was ordained to the subdiaconate on 20 May 1849 and to the diaconate on 2 August 1849.

He was consecrated on 20 December 1863 in Janów Podlaski by Piotr Paweł Benjamin Szymański, bishop of Podlasia,[8] assisted by Józef Twarowski and Henryk Ludwik Plater.

[9] As bishop of Sejny or Augustów, Łubieński reformed the diocesan seminary and organized the diocese into 11 diaconates.