No other details were immediately available.
A drug overdose had been suspected when Hoffman, 46, was discovered. The confirmation puts the actor, regarded as one of the best of his generation, on a growing list of entertainers who succumbed to drugs.
"Glee" actor Cory Monteith, 31, died in Vancouver of an accidental overdose of heroin and alcohol in October. Drugs were also the cause of death of Australian actor Heath Ledger in 2008 and singer Whitney Houston in 2012.
Hoffman's tragic death coincides with an increase in U.S. heroin use, which government officials say has reached epidemic proportions during the past five years.
Hoffman, a best actor Oscar winner for his role in the 2005 biographical film "Capote," won accolades for his versatility and mesmerizing performances on the stage and screen.
From his Tony-nominated role as Willy Loman in Arthur Miller's Pulitzer Prize-winning play "Death of a Salesman" to complex characters in such films as "Happiness," in which he played an obscene phone caller, and "Before the Devil Knows You're Dead," Hoffman transfixed audiences with his talent.
He also earned Tony award nominations for "Long Day's Journey Into Night" and "True West."His screen roles included "The Master," "Doubt" and "Charlie Wilson's War," for which he won best supporting actor Oscar nominations, and appearances in blockbusters such as "The Hunger Games" series.