Over four days, between October 12–16, 1957, the American gangster Joseph Bonanno allegedly attended a series of meetings between some high-level Sicilian and American mafiosi in the Grand Hotel des Palmes (Albergo delle Palme) in Palermo, Sicily – the most splendid in town at the time. The so-called 1957 Palermo Mafia summit has become a legendary landmark in the international illegal heroin trade in popular Mafia non-fiction. The question is if it ever took place. The details of it are still shrouded in mystery. According to some, one of the main topics on the agenda was the organisation of the heroin trade on an international basis. The FBI believed it was this meeting that established the Bonanno crime family in the heroin trade.

The first mention of the "summit" in the United States was during the McClellan Hearings on October 10–16, 1963. Among the American mafiosi present were Joe Bonanno, his underbosses and advisors Carmine Galante, John Bonventre and Frank Garofalo, as well as Lucky Luciano, Santo Sorge, John Di Bella, Vito Vitale and Gaspare Magaddino. While among the Sicilian side there were Salvatore "Little Bird" Greco and his cousin Salvatore Greco, also known as "l'ingegnere" or "Totò il lungo", Giuseppe Genco Russo, Angelo La Barbera, Gaetano Badalamenti, Calcedonio Di Pisa, Cesare Manzella and Tommaso Buscetta.

There are no first-hand accounts of the meeting, except for the version of Mafia turncoat Tommaso Buscetta, who denied a summit ever took place at all. According to Buscetta, Bonanno did stay at the Grand Hotel des Palmes and received many guests all the time, but there was no summit as such.[6] In his memoirs, Joe Bonanno mentions his trip to Palermo, but says nothing about a summit.[7] Professor Alfred W. McCoy does not mention the summit in his landmark book The Politics of Heroin in Southeast Asia, a detailed account of the heroin trade after World War II.

According to Buscetta a gathering took place in a private room at the Spanò seafood restaurant on the evening of October 12, 1957, where Bonanno was fêted as the guest of honour by his old friend Lucky Luciano. Among the other guests were Bonanno’s underboss Carmine Galante, the brothers Salvatore and Angelo La Barbera, Salvatore "Little Bird" Greco, Gaetano Badalamenti, Gioacchino Pennino, Cesare Manzella, Rosario Mancino, Filippo and Vincenzo Rimi, and Tommaso Buscetta. According to Buscetta, it was at this dinner that Bonanno suggested to form a Sicilian Mafia Commission to avoid violent disputes, following the example of the American Mafia that had formed their Commission in the 1930s.

The Italian police had been following Luciano and in so doing found out about the meetings. They observed the gatherings. However, the report was buried in some filing cabinet in Palermo. A copy was sent to the Federal Bureau of Narcotics in Washington. Only eight years later the report was used to indict the participants and some of their associates in Palermo