The shift is scheduled to take place starting Oct. 1.
"This is jail overcrowding on steroids ready to happen, and there's not a darn thing you're going to be able to do about it," said L.A. County Supervisor Zev Yaroslavsky.
Under the state's plan, non-serious and non-violent offenders would become the responsibility of Los Angeles and other counties across the state. In Los Angles, it could be as many as 4,000 over the next few years.
"It's a shell game. State legislature is abandoning their highest priority core mission in terms of public safety, shifting it to the counties, and it is a bait and switch," said L.A. County District Attorney Steve Cooley.
County jails are already under a court order to reduce overcrowding. So where would those new state inmates go?
"We'll either let people go or we can not accept people from the state prison," said L.A. County Sheriff Lee Baca. "Now there are only two options here. Either state prison has the beds or we have the beds."
Officials are complaining the state is trying to balance its budget by shifting the burden to the counties. The first year alone is expected to cost L.A. County about $300 million.
"I don't know where anybody thinks we're going to get $300 million if we're so inclined. This is a state responsibility which has been dumped on counties," said Yaroslavsky.
Officials say inmates will be released to ease overcrowding and then it becomes an issue of public safety.
"There's going to be tens of thousands of people let out all over California who would otherwise be incarcerated, and they are the people who the system has identified as people who are likely to commit additional crimes," said Cooley.
County officials worry that even though the state promises to pay for these inmates, there is no money guaranteed after June 2012. They say after that, they might be stuck with the bill.