Michael Jackson died from cardiac arrest in his rented home
Michael Jackson's death was homicide, primarily caused by the powerful anaesthetic Propofol, the Los Angeles coroner has confirmed.
The singer suffered a cardiac arrest at his Los Angeles home in June, aged 50.
Propofol and the sedative Lorazepam were the "primary drugs responsible for Mr Jackson's death", but four further drugs were also found, the report said.
The coroner's verdict increases the chances of criminal charges being brought against Jackson's doctors.
Police have interviewed his personal physician Dr Conrad Murray but he has not been named as a suspect. He has strenuously denied any wrongdoing.
"The cause of death was established as acute Propofol intoxication," a statement from the coroner said. Propofol is normally administered to patients having surgery in hospital.
WHAT IS PROPOFOL?
A powerful anaesthetic usually used before and during surgery
Can also be used in small doses to reduce stress or anxiety
Produced as a white, opaque fluid and administered intravenously
Marketed under the trade name Diprivan
"The manner of death has been ruled: Homicide," it adds. In the US, homicide refers to the killing of one person by another and includes manslaughter and murder.
A cocktail of drugs - also including sedatives Midazolam and Diazepam, the painkiller Lidocaine and the stimulant Ephedrine - were detected in his body.
The full toxicology report remains sealed, at the request of the LA Police Department (LAPD) and the city's district attorney.
California's attorney general will now open an independent investigation into several doctors whose names have come up in connection with Jackson's death.
David Willis, BBC News, Los Angeles
Michael Jackson had apparently been finding it difficult to sleep in the run-up to a series of comeback concerts in London.
It was Michael Jackson himself who persuaded the company that was promoting his comeback tour to hire Dr Murray, a cardiologist by training, on a salary of more than a $150,000 a month.
Dr Murray has acknowledged administering Propofol and Lorazepam on the day the singer died in an attempt to get him to sleep.
Dr Murray has denied any wrongdoing but it will now be up to the District Attorney to decide whether to lay charges in this case.
Dr Murray's lawyer said the latest information "contains nothing new" and demanded that the coroner's office release the full autopsy report.
Edward Chernoff said he needed to know the exact levels of the various drugs in Jackson's system and said the refusal to release the report suggested "gamesmanship".
"One has to wonder why the coroner felt compelled to release anything at all if the police investigation is not yet complete," he said.
Dr Murray told police he had been giving Jackson propofol as part of his treatment for insomnia, according to an affidavit made public on Monday.
The affidavit said Dr Murray had been giving Jackson propofol daily for six weeks but he was concerned that the singer was becoming addicted to the drug and had been trying to wean him off, using alternative drugs.
Dr Murray told investigators he was not the first doctor to administer propofol to the star.
On the morning of the singer's death, Dr Murray is reported to have given Jackson a lower dosage of propofol - on the singer's insistence - after a number of other drugs had not worked.
Conrad Murray insists he has done nothing wrong
The last time Dr Murray administered the medication was 1040 on 25 June, just hours before Jackson's heart stopped.
Dr Murray is known to have performed CPR on his patient while paramedics were called, but Jackson was declared dead when he arrived at hospital.
Police and federal agents have raided Dr Murray's offices in Las Vegas, Nevada, and Houston, Texas, and a Las Vegas pharmacy that provided the drugs.
Jackson's family welcomed the coroner's findings.
"The Jackson family again wishes to commend the actions of the coroner, the LAPD and other law enforcement agencies, and looks forward to the day that justice can be served," the family said in a statement.
The singer will be buried on Thursday at the Forest Lawn Memorial Park in Glendale, a suburb of Los Angeles, in a private ceremony.
The burial was initially scheduled to take place on Saturday - on what would have been Jackson's 51st birthday.