Ferdinando d'Adda (27 August 1649 – 27 January 1719) was a Roman Catholic Cardinal, bishop and diplomat.

As a member of the family of the counts of Adda, he was a kinsman of Pope Innocent XI,[1] who conferred upon him the titular abbacy of a famous abbey.

Having performed a purely formal duty in Madrid in 1681, Adda was sent by Innocent XI as Papal Nuncio in London during the reign of James II in November 1685,[4] the Catholic Encyclopedia reports that he was charged with the delicate task of inducing the English King to intercede with Louis XIV (then quite inimical to the Holy See) in favour of the oppressed Protestants of France.

[5] He was made titular Archbishop of Amasia,[6] and was consecrated in the Royal Chapel of St James's Palace, in a full Roman Catholic ceremony on 1 May 1687[7] by Dominic Maguire, Archbishop of Armagh, with John Leyburn, Titular Bishop of Adramyttium, and John O'Molony, Bishop of Killaloe, serving as co-consecrators.

"[10] D'Adda was made Cardinal Priest of San Clemente by Pope Alexander VIII in 1690.