Rapper and producer Mac Miller died from "mixed drug toxicity," according to the Los Angeles County Department of Medical Examiner-Coroner.
The drugs in Miller's system included fentanyl, cocaine, and ethanol, the coroner found.
His death was ruled an accident in a report, the results of which were released Monday.
Miller, whose real name is Malcolm McCormick, died in September at age 26.
He started his journey in music as a teenager by putting out mixtapes in his native Pittsburgh. In 2012, his first album, "Blue Slide Park," became the first independent debut album to hit the top of the Billboard chart in more than 16 years. Miller was 19.
He released his fifth studio album, "Swimming," in August.
Miller's family and friends paid tribute to the musician with a concert last week at the Greek Theatre in Los Angeles.
Performers included John Mayer, SZA, and Chance the Rapper.
Miller's ex-girlfriend Ariana Grande also recently honored him in a song called "Thank You," calling him "an angel."
CNN's Stella Chan contributed to this report.