Police say the body of the 44-year-old rock musician was discovered yesterday (08.04.11) in a house in Salt Lake City in the US.
How Mike died is currently unknown, but police say that foul play by another individual is not suspected.
The grunge star - who left the band shortly after the release of their breakthrough 1992 album 'Dirt' - had been arrested three weeks before his death on an outstanding warrant related to an earlier drugs charge, and was also carrying unauthorised prescription medications.
He spoke publicly about his addiction problems on reality TV show 'Celebrity Rehab' last year, on which he tried to overcome his dependence on drugs but appeared to fail.
His untimely passing comes nine years after Alice in Chains was rocked by the death of their singer Layne Staley.
Mike's father told TMZ: "It's a terrible shock and tragedy."