Niccolò I Ludovisi (1610 – 25 December 1664) was Prince of Piombino from 1634 until his death.
He was the son of Orazio Ludovisi, patrician of Bologna and commander-in-chief of the Papal Army (as well as brother of Pope Gregory XV), and Lavinia Albergati. He was the nephew of later-Cardinal Niccolò Albergati-Ludovisi. He was a brother of Ludovico Ludovisi who was made a cardinal by their uncle the pope.
Ludovisi was married three times. After a first marriage (30 November 1622) with Isabella Gesualdo, princess of Venosa, in 1632 Niccolò married Polissena Appiani, the daughter and heiress of Isabella Appiani, Princess of Piombino.
His third marriage in 1644 was to Costanza Pamphili, niece of Pope Innocent X and the sister of Camillo Pamphili who married Ludovisi's niece, Olimpia Aldobrandini.
Niccolo Ludovisi had seven children:
Niccolò was recognized prince in 1634 after paying one million florins. He also inherited his father's titles, becoming marquis of Populonia and duke of Fiano.
He was Spanish viceroy in Aragon (1660–1662) and Sardinia (1662–1664) and in 1657 he was named a Knight of the Order of the Golden Fleece.
Niccolò Ludovisi died at Cagliari, and was succeeded in his state by his son Giovan Battista Ludovisi.