He received his episcopal consecration on the following 29 June from Cardinal Pietro Fumasoni Biondi, with Archbishops Rossi (who by then was Latin Patriarch of Constantinople) and Costantini serving as co-consecrators, in Rome.

Remaining as Albania's apostolic delegate until August 1936, Antoniutti served as a papal envoy to Spain during its civil war on 25 July 1937, for the purposes of exchanging of prisoners and providing assistance to priests who had fled from Communist areas.

[2] Antoniutti was named Nuncio to Spain on 21 October 1953, and created Cardinal-Priest of S. Sebastiano alle Catacombe by Pope John XXIII in the consistory of 19 March 1962.

[citation needed] Seeking a period of rest in his native Nimis, Antoniutti departed from Rome on 1 August 1974, and was instantly killed when his car hit another vehicle on a bypass of Bologna.

His body was moved to Nimis two days later, which would have been his seventy-sixth birthday, for a funeral Mass, which was celebrated by Cardinals Ermenegildo Florit and Albino Luciani, and nine other bishops.