Edwards has committed fully to Wales to the next World Cup in England in 2015 following talks with Welsh Rugby Union's chief executive Roger Lewis.
London Irish, who lie just above the Premiership relegation place, issued a statement on Tuesday confirming Edwards had left his role at the Madejski Stadium.
London Irish director of rugby, Brian Smith said: "I have always been a supporter of Shaun Edwards and that will not change.
"He is a world-class defence coach and has put in place structures, strategies and techniques that we will take forward. I will step up on the defensive side for the remainder of this season.
"We would like to thank him for his efforts over the last six months and wish him well for the future."
There had been speculation Edwards might quit his role as Wales defence coach as he had not been appointed to the British and Irish Lions staff for the tour of Australia by Warren Gatland.
The New Zealander is Edwards' boss in the Wales set-up but the latter's failure to make the Lions coaching team had led to speculation that their partnership might be coming to an end.
But after talks with Lewis, Edwards has given up his other work to concentrate full time on Wales.
"After consultation with Roger Lewis, CEO of the WRU, I am to concentrate solely on Welsh rugby in the build-up to Rugby World Cup 2015," Edwards said in a statement reported by numerous media outlets. "Thus my consultancy work will cease with immediate effect."
- Sports & Recreation
- Shaun Edwards
- Roger Lewis
- Welsh Rugby Union