Sampson, 33, rose to prominence as a teenager when he was called up by former England head coach Jack Rowell in 1996.
He eventually made his debut in 1998 and went on to be capped twice move, while scoring twice against the Barbarians at Twickenham
A 15-year career saw enjoy the Yorkshireman enjoy spells at Otley, Wasps, Bath, Worcester, London Broncos RL, Wakefield Wildcats RL and Blackheath before his move to London Welsh.
Sampson, who was also a regular in the England Sevens side, went on to score 55 tries in 123 appearances for Welsh, helping the side to successive play-off semi-finals.
"After careful consideration, I have decided to announce my retirement as a professional rugby player," said Sampson.
"I would like to take this opportunity to thank the many people who have contributed to the enjoyable career I have been fortunate to experience.
"In particular I would like to thank all my family, who have been a constant source of great strength, inspiration, and support throughout the various challenges that a life in professional sport offers."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.