The bank was founded on February 8, 1919 by the Decree of the President (Jozef Pilsudski) as Pocztowa Kasa Oszczędności. The first director of the bank was appointed on December 28, 1918 - Hubert Linda, the Minister of Posts and Telegraphs. Over time, the Bank organized a headquarters in Warsaw and bank branches in Krakow, Lviv, Łódź, Poznań and Katowice. The main purpose of PKO was adoption of Polish marks instead of Polish zloty. In 1920, the bank became a public institution. During the Second World War, namely 1939-1944, the bank was under the control of the Germans. In April 1945, the bank's activity was resumed. During 1949-1950 PKO was transformed into Powszechna Kasa Oszczędności. In 1974, the Bank began to open current accounts for individuals. From 1975 to 1987, PKO worked under the control of the National Bank of Poland. In 1987, it became an independent bank again by changing its name to Powszechna Kasa Oszczędności Bank Państwowy. On April 12, 2000, the bank was reorganized into a joint stock company called Powszechna Kasa Oszczędności Bank Polski Spółka Akcyjna, which was listed on the Warsaw Stock Exchange on November 10, 2004.