Heavy rainfall over the last two months has led to landslides which have destroyed homes and blocked roads. Weather forecasters say more rain is expected for the region.
In the Santa Catarina state more than 20,000 people have been forced from their homes and up to four towns have been totally cut off.
Neighbouring states are sending equipment and rescue workers to Santa Catarina.
In total more than a million people are said to have been affected by the flooding.
Heavy rain and flooding in Brazil have been known to lead to high death tolls in the past partly because homes are often constructed in dangerous locations that are at high risk and vulnerable to landslides.