"Make no mistake, the possession of this imagery ultimately, in many cases, leads to contact with children, which is why we are so concerned about it," said Salvador Hernandez, Federal Bureau of Investigation.
There are 55 men facing charges of possessing child pornography after the sting operation. A former San Luis Obispo County Sheriff's deputy and a San Bernardino attorney are among the suspects.
Some are charged with additional offenses, such as production of child pornography.
Authorities say the suspects used peer-to-peer networks to exchange graphic images and video. Investigators say some of the victims are infants.
Officials expect further arrests and promise vigorous prosecution.