Sergio Cardinal Sebastiani (born April 11, 1931) is a cardinal of the Roman Catholic Church and the most recent President of Prefecture for the Economic Affairs of the Holy See .

Sebastiani was born in Montemonaco , Italy and was ordained in 1956. In 1976, he became Titular Archbishop of Caesarea in Mauretania , as well as Apostolic Pro-Nuncio to Mauretania and Mauricius . Sebastiani became Apostolic Nuncio, a position similar to that of an ambassador, to Turkey in 1985. In 1994, he was appointed General Secretary of the Central Committee for the Great Jubilee of the Year 2000.

In 1997, Sebastiani was made President of Prefecture for the Economic Affairs of the Holy See, part of the government of Vatican City, responsible for overseeing and managing the Vatican's temporal possessions. He served in this position until the death of Pope John Paul II; because it is customary for most Vatican officials to resign in the absence of a pope, Sebastiani resigned his presidency on April 2, 2005.

Sergio Sebastiani was made a cardinal deacon in 2001, and is eligible to vote at the Papal conclave of 2005