The Spaniard told reporters that Los Blancos are one of the clubs that are continually targeted and said that although he hopes that the problem will one day cease to exist, the issue will never completely be eradicated.
"Real Madrid is one of the clubs that has been on the receiving end of the most racist insults," said Callejon.
"It has happened to us and it is a problem that cannot be completely stamped out. It happened to [Kevin-Prince] Boateng in Italy and it is a matter of serious concern which we all hope will die out one day once and for all."
Real Madrid are currently third in La Liga, 15 points behind leaders Barcelona and four behind local rivals Atletico Madrid.