This article presents a set of sources for research into the First World War, stored in the National Archives in Krakow. The set has been created subjectively, and is restricted to archival materials stored in the branches of Krakow’s archives. The chronology of the set generally covers the period of 1914–1918, although there are also archival resources created during earlier and later periods, which help the research and study into the history of the city, region and other Polish areas. The materials most frequently used in research into the subject are the collections of the Polish Legions and the National Supervisory Committee, the Photographic Collection, the Collection of Placards and Posters, court records, county council records, the Imperial-Royal Police in Krakow, and of town records. An interesting complement to the conducted research are collections of individual and family records, formed both during the War as well as after it. Losses, both demographic and economic, were documented by military and civil powers, among which the most frequently used are the records of: Military Bureau of Care over War Graves Corps No. V in Krakow, the Imperial-Royal Central Commission for the Economic Redevelopment of Galicia in Lwow as well as the National Bureau for the Redevelopment of Galicia in Lwow.