The California Alcoholic Beverage Control Department suspended the Mission Ale House's alcohol license for 10 days because it allowed a minor to enter and remain inside the bar.
The Mission Ale House will also be on probation for one year and will face stiffer penalties if it has another violation.
The bar was cited for similar violations in 2006 and 2007.
The Mission Ale House is located at 97 East Santa Clara Street in San Jose.
The MIssion Ale house is considered one of the most popular bars in the downtown area.
It is known for hosting college gatherings for students at nearby San Jose State University.