This article investigates the formation of recorded sound collections in Belgian and Dutch radio, which initially largely comprised commercial music discs, followed by recordings of radio music, spoken word content and sound effects. It focuses on the creation, management and use of radio sound recordings in the 1930s, as the forerunner to formalised historical archives following the Second World War, proposing to interpret this development in international comparison. The cases are considered in terms of a common experience of war and German occupation (1940-1944/45), and the ‘archive-mindedness’ of post-war radio broadcasters and those tasked with reorganising sound collections impacted by confiscations, looting, and damage. Wartime conditions have led to an uneven source base today, however acknowledging the gaps and omissions in the historical record is a crucial methodological tool when tracing the archival lives of radio, and the process by which radio came to be seen as a significant site of (national) history and heritage.