With the change of government in January 1933, Körting's SPD and union activities became illegal: he resigned from all his political positions and lost his job at Agfa. Later in 1933 he was detained for eight months at the Oranienburg concentration camp. On his release he was able to find work as an agricultural labourer, and later during the Nazi years he worked as manager of an agricultural enterprise. As a former SPD member of a legislative assembly he lived under on-going Gestapo supervision, however, and was subjected to several more periods of state detention. War resumed in 1939, and towards the end of the war period, in July 1944, he was caught up in the (and worse) that followed the failure of the Hitler Assassination plot in July 1944. In July or August Otto Körting was arrested and placed in the Buchenwald concentration camp: sources differ as to whether his detention lasted for four months or longer. After his release he settled down at his little farm in Bobbau.