 Caggiano was appointed the first bishop of the newly erected Diocese of Rosario on 13 September 1934, for which he was consecrated on 14 March 1935.Pope Pius XII elevated him to Cardinal on 18 February 1946.In his 2002 book "The Real Odessa" Uki Goñi showed that Argentine diplomats and intelligence officers had, on Perón's instructions, vigorously encouraged Nazi and Fascist war criminals to make their home in Argentina.