Haim starred in a string of hit movies as a child and teen in the 1980s, but his career was eclipsed by an addiction to drugs that lasted most of his life. He died March 10 at the age of 38 after complaining of flu-like symptoms and was buried this week in his native Toronto.
The actor's mother, Judy, has said the coroner's office told her Corey suffered from pulmonary congestion and an enlarged heart.
E! News said that although the death certificate was issued for the former child star Thursday, the official cause of his death will not be determined until after toxicology test results are analyzed.