Ny Dag was started in 1930 by the branch of the Communist Party that had selected to remain faithful to Comintern in the big party split of 1929, in order to replace Folkets Dagblad Politiken, which had been the party's main publication since 1917, but had selected to join the "Kilbom rebels" in the 1929 split.
Ny Dag was one of six newspapers that was subject to a transport ban during the Second World War.
[2] In early 1942 one of its issues was banned since it covered a comment on the publication of a document by the Polish government in the anti-Nazi newspaper Trots allt!.
[4] About ten local editions of Ny Dag were launched during the 1940s.
[7] Ny Dag was printed at Västermalms Tryckeri AB, on Kungsholmen in Stockholm.