Houston was one of the most celebrated female singers of all time, with hits including I Will Always Love You and Saving All My Love For You.
But her later career was overshadowed by substance abuse and her turbulent marriage to singer Bobby Brown.
Ms Houston died on the eve of the Grammy Awards in Los Angeles. She had been due to attend a pre-awards party in the Beverly Hilton Hotel organised by her long-time mentor and record industry executive Clive Davis on Saturday evening.
He went ahead with the party, holding a minute's silence and telling the audience he was "personally devastated by the loss of someone who has meant so much to me for so many years".
The hotel was already teeming with reporters and celebrities when police received an emergency call from hotel security at 15.43 local time (23:43 GMT), Beverly Hills police spokesman Mark Rosen told the BBC.
Police were despatched, but paramedics, already at the hotel because of the party, attempted to resuscitate her, without success. She was pronounced dead at 15:55.
Mr Rosen said Ms Houston's entourage - comprising family members, friends and co-workers - had taken over much of the fourth floor of the hotel.