Jameson was taken into custody by police after crashing her car into a lamppost in Orange County, Calif., in May and she was hit with three misdemeanors for DUI, having a blood alcohol level of 0.08 percent or higher and driving a motor vehicle with a suspended license.
Her lawyer entered the not-guilty plea on her behalf during a court hearing on Wednesday. Jameson, 38, did not attend.
A pretrial hearing has been set for Aug. 16. Jameson faces up to a year behind bars if convicted.