Police are investigating her death as an apparent suicide.
The 55-year-old was found dead in her Park Avenue apartment at 10:20 local time (15:20 BST) by her housekeeper, a law enforcement official said.
Kate Spade was well known as a designer of clothes, shoes, and jewellery, but was best known for her accessory line. She co-founded Kate Spade Handbags in 1993 with husband Andy Spade.
The company opened its first store in New York in 1996, and now has more than 300 branches worldwide.
It is recognisable for its distinctive logo which features the spades playing card symbol, in reference to the designer’s surname.
Source : CNN.COM