This research endeavors to provide a comprehensive examination of the involvement of Ukrainian soldiers in the Polish Armed Forces during World War II, with a particular focus on their participation in the Battle of Monte Cassino. Utilizing newly discovered archival materials from both Polish state archives and private family collections, as well as oral and narrative sources confirming Pavlo Odrekhiwskyis role in the Polish Armed Forces between 1939 and 1946, this article expands and enhances our understanding of the experiences of Ukrainians who became part of the Army of General Vladislav Anders. Research methodology is based on the general principles of scientific work: systematicity, reliability, logic. The study delves into the participation of Ukrainian soldiers in the 5th Regiment of Sappers during the battles of September 1939, their subsequent capture by Soviet forces in Ternopil, and their forced labor in the Krivyy Rih Ore Basin and the NKVD camp in Kotlas. It further explores the formation of the Polish army from war prisoners and other detainees under General Vladislav Anders' command, shedding light on the heroic journey of Ukrainians within this army. The article culminates with an account of the Battle of Monte Cassino and the challenging fates of its participants in the former Soviet Union after World War II.