Kelly had a fatal mixture of drugs in his system, according to an investigator from the Fulton County Medical Examiner's office.
Kelly was found dead in his Atlanta home on May 1. He was 34.
His mother said Kelly had a history of drug abuse, specifically of cocaine and heroin, and had episodes similar to the one that hospitalized the rapper before his death.
The toxicology report did not specify which drugs were found in Kelly's body.