The blaze erupted at this club in Santa Maria that was packed with about 2,000 college students.
Witnesses say it started when the band performing on stage lit a flare or fireworks.
In seconds, the club started filling with thick smoke that set off a panic and a stampede. Several young men tried chopping into walls with axes to save the people trapped inside.
One of the survivors described the chaos before a man dragged her to safety.
A local resident said, "There was some kind of small gate, that was chained and with all of the people pushing against it, it broke... Then people started going under the gate but I was afraid to do that because I was afraid I would get killed by people running over me."
Officials say the cause of the fire is still under investigation but a police inspector tells a Brazilian news agency the band was to blame for a pyrotechnics show and that manslaughter charges could be filed.