Royal Ascot is facing "heightened security measures" in the wake of the UK terror attacks.
Guy Henderson, CEO of Ascot, says racegoers will experience "extensive bag, dog and physical searches" at the annual event.
The race meeting is attended by The Queen and senior members of the royal family every day.
In a statement he also warned that there will be a "stronger armed and uniformed police presence."
The new measures have been introduced because he says the safety of revellers is paramount.
In a statement Mr. Henderson said, "There will be more extensive dog, bag and physical search procedures for everyone at all the racecourse entrances and you will notice a stronger armed and uniformed police presence throughout the site and the vicinity.
"The safety of all our racegoers is paramount and you can be assured that the racecourse works extremely closely at all times with the Police, the Security Services and our specialist advisers in implementing the appropriate security measures for your protection."
He added: "It is inevitable that access to the racecourse this year will take longer.
"Please be prepared for this and allow sufficient time. Please also bear in mind that if you exit at any stage, you will need to pass through security to re-enter."
And he urged racegoers not bring unnecessary bags or luggage into the racecourse.
Luggage storage facilities will be provided outside of the course enclosures.
"We ask for your understanding, patience and cooperation with us and that you also inform your guests and party members of this update.
"We also ask for your vigilance on matters of security. If you see or hear anything suspicious, please bring it immediately to the attention of the Police or our Stewards," Mr Henderson said.
Ascot Racecourse’s website will contain updates on security.
