The WRU has praised Craig White for his excellent contribution to Welsh rugby and the input he has delivered to improve the general fitness levels and training techniques employed by elite Welsh players.
Craig White's fitness remit with the Welsh squad will now be taken forward by Head Strength and Conditioning Coach Adam Beard who has been in place since 2009.
The Wales team management will announce more important changes to the performance team structure in the New Year.
Craig White is renowned as one of sport's most accomplished conditioning coaches and has been working within the WRU national squad structure since 2008.
He said: "I have enjoyed working with some great people here in Wales, but with my focus now on new career horizons I have decided to leave in January to allow a new structure to plan and build towards Rugby World Cup 2011.
"I always devote myself totally to any challenge I accept so it would be wrong to continue in place while I was pursuing this new career direction.
"I have made a lot of good friends in Wales and I will be watching the team's progress with interest and wish them all well for the challenges ahead."
Wales Head Coach Warren Gatland said: "Craig White has made a huge contribution to Welsh rugby which has helped the squad achieve excellent fitness and conditioning levels.
"Craig has also been instrumental in helping us restructure our systems and structures in alignment to the four Welsh Regions which is another important factor in our continued improvement.
"I want to thank him personally and on behalf of Welsh rugby for the skill and dedication he has shown throughout his time in Wales.
"I know he is sorry to be leaving before the Rugby World Cup, but Craig is not the sort of man who would want to remain in place after he has decided that his career focus lies elsewhere. We all wish him well on his new venture."
WRU Group Chief Executive Roger Lewis, said: "I want to thank Craig White for the excellent contribution he has made to Welsh rugby over the last two years.
"I am particularly grateful for the way he has made his decision at this timely juncture to help Warren and his management team review their needs. I know there will be some further announcements in the New Year and I am confident we are in great shape for the challenges ahead.
"Craig been part of an evolving structure which is now envied across the elite rugby environment and I thank him for the role he has played in that transition.
"2011 is set to be a year of great opportunity for Wales and we are in excellent shape to meet the challenges ahead.
"We have secured our Head Coach under contract for another four years, restructured within his back room team and unveiled a fantastic schedule of international fixtures for several years ahead.
"We will never be complacent, but it is very satisfying to know that our players will be coached and prepared by the best professionals available at one of the finest facilities in world rugby at the WRU National Centre of Excellence."