Police raided the Happy Land Internet Café on the 10900 block of Magnolia Avenue Friday.
Officials said 15 people were arrested on charges of illegal gambling, drugs, or prostitution.
Thirty gaming computers were seized along with an undisclosed amount of cash.
Detectives also raided a Rancho Cucamonga home suspected of having a link to the café.
The raids were part of a two-month probe into the illegal gaming operation at the business.
Anyone with information regarding the case was urged to call Riverside police at (951) 363-7204.