Giovanni Antonio Guadagni, OCD (14 September 1674 – 15 January 1759), religious name Giovanni Antonio di San Bernardo – was an Italian Discalced Carmelite and cardinal of the Roman Catholic Church.

Guadagni later travelled to Rome to practice law but upon his return to Florence in 1697 decided to become a priest.

[1] He made his solemn profession of vows on 1 November 1700 and would undertake theological and philosophical studies in Florence at convents that the order managed.

Pope Benedict XIII appointed him as the Bishop of Arezzo on 20 December 1724 and he received his episcopal consecration a week later in Santa Maria della Scala church from his uncle and future pope Lorenzo Corsini.

His uncle's election as pope brought the bestowal of the pallium on Guadagni in the chapel of the Quirinal Palace on 22 November 1730.

On 10 April 1750 (two months after being made the Frascati titular head) he entered the Frascati suburbicarian see to commence a pastoral visit and oversaw the restoration of several churches while presiding over Confirmations and other Masses as well as leading rosaries.

He died in Rome in 1759 and was buried at the left side of the main altar in Santa Maria della Scala in the tomb that he had constructed for himself.

[3] But the cause stalled at some point and remained dormant until it was reactivated under Pope Pius XI on 26 November 1938.