The contents of the note were not released by the coroner's office, which is charged with formally identifying the circumstances of the designer's death.
Days before his body was found Thursday, McQueen had left several messages on the social networking site Twitter revealing his grief at the death of his mother days earlier.
Coroner's officer Lynda Martindill said the 40-year-old McQueen had died from asphyxiation and hanging. Full details of the autopsy will be available in a few months.
There were no suspicious circumstances in the death, and authorities suspect no malice, police detective inspector Paul Armstrong testified. After a five-minute hearing Wednesday, coroner Paul Knapman adjourned the inquest until April 28. The inquest has yet to formally rule McQueen's death a suicide.
McQueen - one of British fashion's brightest stars - had posted messages four days before his death about his "awful week," and said he had to "somehow pull myself together and finish."
Known for his dramatic statement pieces and impeccable tailoring, McQueen dressed celebrities from Cameron Diaz to Lady Gaga and influenced a generation of designers.