The demonstrators were trying to set up tents at the Ronald Reagan Federal Building. Police said they violated an ordinance against camping and were taken into custody at around 10:15 p.m.
They say the protesters were given ample warning.
"They were initially issued citations and told they have to leave and failed to do so," said Cpl. Anthony Bertagna from Santa Ana Police. "They were advised again and given 20 minutes to leave, but they didn't so they've been arrested."
"We hope to make more than anything a statement," said Occupy O.C. protester Jose Hernandez. "Let them know that we're willing to get arrested for the sake of letting the public know this is what it's going to take, sadly, for us to make a change."
The protesters were demonstrating in solidarity with those occupying Wall Street, and say they'll be back on Sunday.
They have a two-day permit to march and demonstrate peacefully, but are not permitted to set up any type of camp.