The Poznań Branch of the PAN Archive in Warsaw was established in May 1956. From April 1974, the headquarters of the Branch was located in the building of the Poznań Society of Friends of Sciences in Poznań. The Archive collects, processes and makes available archival materials on the activities of the Polish Academy of Sciences and legacies of scholars. The legacies that form the backbone of archival resources are gathered through purchases, donations and deposits. Then they are compiled in the form of inventories and made available for research purposes. The collections of the Archive of the Polish Academy of Sciences in Poznań contain rich documentation of the history of science in Poznań and in Poland. They concern both scientific institutions, including laboratories, editorial offices and some institutes of the Polish Academy of Sciences, the University of Adam Mickiewicz in Poznań and other Poznań universities, as well as biographies of individual scientists, especially those connected to Poznań and Greater Poland. Archival collections with valuable materials related to groundbreaking events in the post-war history of Poznań and Poland are also interesting. Archival collections are also displayed at exhibitions and during scientific conferences. Archives from two legacies are available on the CYRYL portal – the Poznań Local Digital Repository.