In the summer of 1990, Carboni joined A.S. Roma, being an undisputed starter during his seven-year spell, with the exception of the 1992–93 campaign due to a serious injury. Under manager Ottavio Bianchi, he won the Italian Cup in 1991 in a 4–2 aggregate victory over former club Sampdoria; he also appeared in the first leg of the UEFA Cup final that year, which ended in a 2–0 defeat to Inter Milan.