As the Thrash phenomonen swept the Rock world in the mid 80's Australia was not to be left out. Sydney's MORTAL SIN had been forged in 1985 consisting of vocalist Mat Maurer, guitarists Paul Carwara and Mick Burke, bassist Andy Eftichiou and ex-WIZZARD drummer Wayne Campbell. Both Eftichio and Carwara are both former JUDGE members. MORTAL SIN's career was given an enormous boost when editor Bernard Doe of British Metal magazine 'Metal Forces' was asked by the major Vertigo label, which Thrash Metal acts they should be looking at. Doe suggested MORTAL SIN and the band were soon signed up.

MORTAL SIN had, alongside SLAUGHTER LORD, been at the forefront of the Australian Thrash scene and it was their self financed 'Mayhemic Destruction' album which had caught Doe's attention as he gave it 99 out of a 100 in his review. When SLAUGHTER LORD folded the path was clear for MORTAL SIN and Vertigo quickly repackaged and reissued the album internationally.

MORTAL SIN's debut album featured former WIZZARD man Keith Krstin on guitar, he was superseded by SLAUGHTER LORD's Mick Burke for subsequent touring.

MORTAL SIN's next album, 'Face Of Despair' produced by Randy Burns, was issued in time for the band's support slot on METALLICA's 1989 Australian tour. In July of the same year replaced drummer Campbell with another erstwhile SLAUGHTER LORD man Steve Hughes for European jaunts opening for EXODUS and FAITH NO MORE. Campbell created WHITE TRASH then GRUNGEON with ex-SUICITY guitarist Doug Dalton.

In early 1990 Maurer bailed out, to create OMEGA in alliance with members of DEATH MISSION and UTI, and the band plugged the gap with Steve Sly. Touring across Europe had the band as opening act for TESTAMENT throughout January before hooking up with FAITH NO MORE for their UK gigs. A short burst of North American gigs closed with a Los Angeles gig at The Whiskey on 21st February, Mat Maurer's last show with the band. Upon their return to Sydney MORTAL SIN effectively split in two when Carwana, Hughes and Burke all quit. Burke and Hughes formed PRESTO with singer Luke Pittman and bassist Aaron Hodge.

MORTAL SIN persevered filling the gaps with former ENTICER guitarist Dave DeFrancesco, ex-RAGS N' RICHES guitarist Alex Hardy and former WHITE WIDOW drummer Nash Hall. This line up guested for MEGADETH on their 1991 Australian trek although shortly after Tom Doustopil replaced Hardy.

MORTAL SIN cut a new record, the more Power Metal orientated 'Rebellious Youth' produced by Kevin Shirley', in 1991. The record was retitled 'Every Dog Has It's Day' for it's European release on Music For Nations.

Struggling to survive MORTAL SIN folded in 1992. Eftichio was soon back in action with WHO'S GUILTY. Their sole release, the 1994 'Revenge' EP, featured Eftichio, vocalist Sean Bosco, guitarist Bruno Gerace, keyboard player Bob Wheatley and drummer Nick Pansini.

In late 1996 MORTAL SIN reformed with Mat Maurer, Andy Eftichiou, Paul Carwana, Wayne Campbell and Anthony Hoffman. Carwana soon lost his place to former THIS THING and WHITE TRASH guitarist Troy Scerri as the band embarked upon a headline club tour. A mini album, 'Revolution Of The Mind' comprising of new material, archive demos and live tracks, arrived in 1997. Just upfront of an appearance at the 'Metal For The Brain' festival lonstanding lynchpin of the band Andy Eftichiou decamped. The show was conducted with Chook from TSCABEZE but MORTAL SIN collapsed soon after. Troy Scerri founded Stoners DAREDEVIL whilst Wayne Campbell ocuppied himself with CONVICT.

The band reformed in early 2004, counting a line up of original members Mat Maurer on vocals, Wayne Campbell on drums, and Andy Eftichiou on bass, alongside ex-ADDICTIVE guitarists Joe Buttigieg and Mick Sultana. This latest version of the band performed their debut gig on 5th March 5 at the Annandale Hotel in Sydney, supported by LYCANTHIA, RAMPANT and KHEMIST. This gig was scheduled to be filmed for a subsequent DVD release. However, a further round of membership changes saw both drummer Wayne Campbell and guitarist Joe Buttigieg opting out and the recruitment of Luke Cook and Nathan Shae respectively.

In May MORTAL SIN grabbed the valuable tour support to ANTHRAX's Australian dates. The band supported SLAYER and MASTODON on April 17th 2007 at the Hordern Pavilion in Moore Park. The album 'An Absence Of Faith' was released in Europe in November 2007. MORTAL SIN performed at the 'Metalmania' festival on 8th March 2008 at Spodek in Katowice, Poland.

MORTAL SIN commenced songwriting sessions for a new album in March 2009.