Count Igor Cassini Loiewski (September 15, 1915 – January 5, 2002) was a Russian-American syndicated gossip columnist for the Hearst newspaper chain.

Igor worked as a publicist, ran the Celebrity Register, edited a short-lived magazine called Status, was a co-director of the fashion company House of Cassini, founded by his elder brother, Oleg Cassini, and was a television personality in the 1950s and 1960s, until he was convicted of being a paid agent of the dictator of the Dominican Republic Rafael Trujillo without registering, as required by U.S.

Cassini himself later reflected, "From an obscure junior society columnist always worried as to how I would ever find enough material to fill the space I was grudgingly given, I became national news overnight.

The term "café society" had been invented by Maury Paul, Cassini's predecessor as "Cholly Knickerbocker" at the New York Journal American.

After Trujillo died in 1961, the new government of the Dominican Republic released evidence showing that Cassini had been hired on the basis that he could use his contacts and those of his brother, Oleg, one of the First Lady's favorite dress designers, to influence the Kennedy Administration.

He was born in Sevastopol, Russian Empire, and his elder brother, Oleg Cassini, became a fashion designer best known for dressing First Lady Jacqueline Kennedy.

Charlene Cassini also suffered from headaches following a minor household accident, was depressed after the suicide of a ski instructor friend, and had become bitterly estranged from her father.

After his wife's death, Cassini later wrote, "We discovered the apartment, particularly her closets, littered with all kinds of pills, hidden in vases, under linens, stuffed in her shoes and the pockets of her clothes."