Mijatovic has been critical of Barca in recent weeks since Edmilson's "black sheep" controversy and claims the atmosphere inside the Real dressing room is much brighter.
But Valdes snapped: "(Mijatovic) must have cameras in the locker room to see what's happening here...
"The environment at Barcelona has been good for many years. We are a close group of players, who come to work every day aware of the responsibility that comes with playing for Barca."