The Irish singer was in London for a short recording session when she passed away.
Her publicist confirmed the tragic news tonight, saying: "Family members are devastated to hear the breaking news and have requested privacy at this very difficult time."
Dolores has been the lead singer for The Cranberries since the 1990s and led the band to international success with hits such as Linger and Zombie.
The Limerick-born star is known for her strong Irish accent.
As well as playing with the band, Dolores also toured with D.A.R.K and appeared as a judge on RTE's The Voice of Ireland in 2o13/2014.
She was married to Duran Duran's former tour manager Don Burton for 20 years but they split up in 2014.
The couple had two children together - Molly Leigh, 16, and 12-year-old Dakota Rain.