Rosario DeSimone (Italian pronunciation: [ro'za?rjo desi'mo?ne]; 11 December 1873 – 15 July 1946), was the head of an Italian crime family during the 1920s to 1940s that was the predecessor to the Los Angeles crime family of the American Mafia.
Rosario was the father of the future California mob boss, Frank DeSimone.
He is not to be confused with the Chicago Italian Timothy Rosario DeSimone.