Prospero Marefoschi (24 September 1653 – 24 February 1732) was a cardinal of the Roman Catholic Church.
He was born in Montesanto, now part of Potenza Picena, in the region of Marche, Italy.
He was ordained as a deacon in 1709 and archbishop in 1711.
He was made a cardinal by Pope Benedict XIII on 29 December 1724.
He participated in the papal conclave of 1730.Cardinal Mario Marefoschi was his nephew.