Frank "Flowers" D'Alfonso, an influential associate of the former Bruno crime family boss Angelo Bruno, is murdered by seven members, including soldier Eugene "Whip" Milano, belonging to Nicodemo "Little Nicky" Scarfo's organization for refusing to pay a street tax to Scarfo.
May 11 - The leaders of the alleged New York's Five Families are charged by the Federal Bureau of Investigation as the result of a major prosecution into organized crime.
June 25 - Colombo crime family leader Carmine "Junior" Persico is charged with extortion and murder.
September - The Sicilian Mafia boss Pino Greco of the Ciaculli family is killed on the orders of Salvatore "Toto" Riina. Greco had become a very influential member of Cosa Nostra after the 1981-83 war who not only inspired fear, but also had a loyal following with the younger men of honor. This was seen as a threat to Riina's control and, with Greco's wartime service all but forgotten, he was considered expendable.
October 10 - Opening statements commence in the Federal trial United States of America v. Paul Castellano, et al.. Gambino boss Paul Big Pauly" Castellano and nine others were accused of operating an international auto-theft ring that shipped stolen cars to Kuwait and Puerto Rico, among other destinations. The defendants were also accused of committing five murders to protect the interests of the operation.
December 2 - Aniello "Mr. Niel" Dellacroce, underboss of the Gambino crime family, dies of brain cancer. A protégé of Albert "The Mad Hatter" Anastasia (also a mentor to future Gambino leader John "Johnny Boy" Gotti), having been passed over for leadership of the organization for the less popular Paul Castellano and the fact that "Big Paul" didn't pay his last respects to his loyal underboss at the wake causes much animosity throughout the organization. Despite Dellacroce's wishes for its members to remain loyal to the boss, his death triggers a coup against boss Paul Castellano.
December 16 - Gambino crime family boss "Big" Paul Castellano is murdered, along with his new underboss and bodyguard Thomas "Tommy" Bilotti, outside of Manhattan's Sparks Steak House. John Gotti, the prime suspect in Castellano's assassination, quickly assumes leadership of the Gambino crime family.
December 19 - Michael Franzese, a top capo in the Colombo crime family, is indicted under the RICO Act in connection to selling gasoline to retailers while failing to pay federal, state, and local taxes. Franzese is the son of legendary Colombo Family member Jonn "Sonny" Franzese and is one of the biggest earners in Cosa Nostra history at one time making $5 million in cash per week for three years from his gasoline-bootlegging operations, delivering 30% to the Colombo hierarchy each week.