According to the report, the 48-year-old singer had cocaine in her system at the time of her death. Her death was ruled as accidental and coroner's officials cited heart disease and cocaine use as contributing factors.
Houston died Feb. 11 after drowning in a bathtub at the Beverly Hilton. The report said it was Houston's assistant who found her lying face down in a bathtub filled with water. She and a bodyguard pulled the singer out of the tub and then asked the hotel to call 911.
Investigators said they found a spoon with a white crystal-like substance in it and a rolled up piece of white paper from off the top of a counter.
"I also collected remnants of a white powdery substance from out of a drawer" and from a mirror found in the bathroom, coroner's supervisor Kristy McCracken wrote in the report.
She was nude, submerged entirely in 90-plus degree bath water for about one hour, the report says.
The report also says "an ashtray with multiple cigarette butts" was in the bathroom and a "plethora" of prescription medication bottles were collected in the hotel room.
The singer had battled addiction for years. An investigator noted in the report a hole in the singer's nose that was listed under "history of substance abuse." Friends and family said she was trying to make a comeback in the months before her death.
On her final day alive, Houston complained of a sore throat, and an assistant suggested she take a bath before preparing for a pre-Grammy party, according to the report.
The coroner has stressed that foul play is not suspected.
See photos of Whitney Houston celebrating just hours before she died.
The Associated Press contributed to this story.