The 34-year-old -arm spinner has been struggling with a hip injury for over a year and is now set to formally announce his decision to give up the game at The Oval, where he helped England secure the Ashes two years ago, on Saturday.
It was with Oval-based Surrey that Giles began his career as a seamer before joining Warwickshire.
Giles took 143 wickets in 54 Tests and one of his best performances came during his final appearance at The Oval where he made a Test-best 59 and shared in a decisive 109-run eighth wicket stand with Kevin Pietersen, which secured the draw that won the Ashes.
He then played in the first two Tests in Pakistan that November before being sidelined with his injury problems.
But he recovered in time to be controversially chosen ahead of Monty Panesar for the first two Tests of the 2006-07 Ashes.
However, after returning home early from Australia for family reasons, he got injured again and has now had three operations in the last 18 months.
Speaking a few weeks ago, Giles said he was considering his future after seeking advice from several medical specialists.
"It's a difficult time because cricket is what I do and cricket is what I've done for 20 years, but I do have to start thinking about the implications," Giles said.
"It's great to keep going and saying to yourself: 'I'll be fine', but the chances of recurrences are very high and I can't keep going through operations.
"I've never thought it's not worth it, but I have to start thinking about it. If, in five years' time, they think this will have done more damage then I'll have to take that advice - I certainly don't want to be looking at hip replacements."
Giles, who also played 62 one-day internationals, is now set for a career in the media having already broadcast on the ongoing England-India series, for BBC Radio Five. The third and final Test started at The Oval on Thursday.