Senate President Don Perata ordered the rare legislative lockdown in a standoff over whether to cut a tiny fraction of the proposed $145 billion state budget.
Perata told his Republican counterpart to come up with his own version of the budget so the Senate could reconvene Wednesday.
"We have no freakin' idea where you want to go," Perata told Sen. Dick Ackerman.
Republicans are demanding a balanced budget. They rejected a spending plan passed by the Assembly that reduces the state's operating deficit to about $700 million, about one half of 1 percent of the overall budget.
Overnight, lawmakers needed permission to exit the chamber. Some slept at their desks, listened to iPods or read. Others huddled on the Capitol balcony drinking wine and beer from plastic cups.
Gov. Arnold Schwarzenegger tried to convince Republicans to vote for the plan, but left his Capitol office shortly after 2 a.m. Saturday, all but ending any hope for a quick resolution.
The budget already is long overdue, with the state's 2007-08 fiscal year having begun July 1. Lawmakers also were to begin their summer recess Friday, but late in the evening Perata ordered senators locked in the chamber until they reached a deal.
Senate Republicans remained unified in their opposition to the spending plan because it doesn't go far enough to eliminate the state's operating deficit, Ackerman said.