More than 60 people have been cautioned for drug possession and ejected from the V Festival site in Staffordshire.
About 90,000 people have been expected at the event in Weston Park near the Staffordshire and Shropshire border.
Eighteen crimes were reported, including 13 thefts from tents, and 21 arrests were made, Staffordshire Police said.
Earlier the medical staff said 136 people had visited an on-site medical centre.
Gates opened at Weston Park for festival-goers on Friday ahead of the event on Saturday and Sunday.
Sixty three people were cautioned for drug possession and ejected from the site, police said.