On Saturday, President Evo Morales formally unveiled his new constitution; he says it will give more power to the majority indigenous population.
After the presentation, the president celebrated with his supporters in La Paz.
But Santa Cruz - and three other regions - objects to the plans, which it says will mean greater central control.
Santa Cruz governor Ruben Costas backs greater autonomy for his region, and presented his own document at his own ceremony.
Many people in Santa Cruz back a plan to retain two-thirds of taxes, instead of sending the money to central funds.
Santa Cruz artist Henry Flores has produced a pro-autonomy banknote
However, many indigenous people support President Morales' initiative
The president, who came to power two years ago, has considerable support, especially in rural areas.