Paris Hilton was stopped in her car and arrested for possession of cocaine in Las Vegas on Friday night.
Clark County Detention Center held Paris Hilton on a charge of possession of cocaine.
She was later released but police did not reveal when she would face a court hearing.
Police spokesman Lt Marcus Martin said the 29-year-old socialite was in a car driven by a friend, which was stopped when officers noticed suspected marijuana smoke coming from it.
Mr Martin said that during the search officers found what appeared to be a controlled substance on Miss Hilton. Tests showed that it was cocaine.
Police were unable to confirm how much of the drug she had in her posession.
Two months ago Miss Hilton was arrested during the World Cup in South Africa for marijuana posession.
She and a friend were accused of possessing the drug at the Brazil v the Netherlands quarter-final, but the charges were later dropped.
The hotel heiress was arrested in June 2007 for driving offences.
After spending about 23 days in jail, Miss Hilton told US television host Larry King that the experience caused her to re-evaluate the role partying played in her life. She said she wanted “to help raise money for kids and for breast cancer and multiple sclerosis.”
