City News Service says a federal jury in Los Angeles convicted the six Monday of conspiracy and obstruction of justice after a week of deliberation.
Two sheriff's sergeants, two lieutenants and two deputies are now facing up to 15 years in prison.
Two defendants also were convicted of making false statements for telling an FBI agent involved in the jails probe that she could face arrest.
Prosecutors say the six conspired to hide an inmate informant from the FBI so he couldn't testify about alleged brutality of inmates at LA County jails.
The Sheriff's Department claimed the man was transferred to another location for his own protection.