The Irishman's contract at the IRFU expired at the end of the 2008 Six Nations and he joins the Ospreys after a summer of speculation that saw him approached by both the New Zealand and England Rugby Unions as well as Gloucester RFC and Waikato.
McGurn said: "The prospect of joining the Ospreys and carrying out a key role for such a progressive and forward thinking organisation was quite simply too good to turn down. When I first came to meet Andrew Hore I was struck by the fantastic atmosphere within the set-up, it just felt like an outfit with massive potential to be successful. I've worked closely with Munster over the last year and I can sense a similar feeling here.
"I've had a number of options to consider over the summer, some of which were very tempting, but I felt that the Ospreys offer was best for me personally and professionally.
"I believe that I can have a greater impact working with players on a day-to-day basis rather in the piecemeal fashion you do in the international game. This will allow me to develop further and move closer towards my ultimate aim of becoming the best fitness coach in the world.
Ospreys Elite Performance Director Andrew Hore said: "To be able to confirm the appointment of Mike McGurn as Head Conditioning Coach is a huge coup. He is extremely highly regarded in the conditioning world and his decision to join the Ospreys is a massive statement of intent for both him and the region.
"He is a strong character who has been one of the driving forces in the Irish game for the last six years, a period which has been their strongest in recent history. At the Ospreys he will be instrumental in driving our core values and behaviours and will a play a significant senior role within the management team."
Prior to working in the Ireland set-up, 37 year-old McGurn enjoyed huge success in rugby league as fitness coach for the St Helens team that won the treble of Challenge Cup, Super League and World Club Championship in the 2000-01 season. He has also worked in similar roles for Hull City FC and Leinster Rugby and, whilst attending university in Philadelphia, he gained valuable experiences in a range of sports, with Philadelphia Eagles (NFL), Philadelphia Flyers (NHL) and Philadelphia 49ers (NBA).
Irish international winger Tommy Bowe, who signed for the Ospreys from Ulster this summer, is one player who has already worked closely with Mike McGurn and he says that the appointment will be a huge boost for his new team:
"I've worked with Mike over the last four years and he has had a significant influence over my strengthening and conditioning work, as he has with the rest of the Ireland squad. He is extremely highly regarded within the camp there and I have no doubt that will prove to be the case at the Ospreys. He'll push the boys hard in training but the difference he can make is incredible, and I'm sure we'll all see the benefits."