Jackson suffered a cardiac arrest in June
Michael Jackson's death certificate has been amended to reflect his cause of death as homicide.
The document has been changed to specify that his death was caused by "injection by another".
Investigators had concluded that a powerful concoction of prescription drugs killed the pop star.
The coroner's further homicide verdict increases the chances of criminal charges being brought against Jackson's doctors.
Jackson died at his Los Angeles home in June, aged 50.
Police have interviewed his personal physician Dr Conrad Murray but he has not been named as a suspect. He has strenuously denied any wrongdoing.
Jackson is expected to be buried in a private sunset ceremony in the Forest Lawn Memorial Park in California.
Only close family and friends of Jackson will be in attendance for the event.
Meanwhile, a hoax video apparently showing the singer emerging from a coroner's van has emerged.
German channel RTL posted the footage on YouTube and received 880,000 hits in one day.
Heike Schultz, spokeswoman for the network, said it had been an experiment.
"We wanted to show how easily users can be manipulated on the internet with hoax videos," she said.
"Therefore, we created this video of Michael Jackson being alive, even though everybody knows by now that he is dead - and the response was breathtaking."