South Central Ambulance Service and South East Coast Ambulance sent out land and air crews to an area near the Discovery Centre at Swinley Forest, Crowthorne at 15:57 BST on Saturday.
Crews were responding to reports that a man had come off his mountain bike. The cyclist died at the scene.
The man's death is not being treated as suspicious. His name has not yet been released.
A male cyclist died at a popular mountain biking area in Berkshire.