Tameka Cottle was charged with possession of ecstasy on Friday and she is due in court for an arraignment on Nov. 1 in Beverly Hills.
The 35-year-old was arrested along with her husband during a traffic stop on the Sunset Strip on Sept. 1.
Prosecutors on Monday declined to charge T.I., citing a federal judge's decision to send him to federal prison for 11 months for violating his probation on weapons charges and the small amount of drugs found on him.
A charge evaluation sheet said deputies found four ecstasy pills on the Grammy Award winner.
The Associated Press contributed to this report.