In Belo Horizonte, where the game was held Tuesday, 12 people were arrested after fighting broke out in bars and streets in the bohemian neighbourhood of Savassi, a favourite tourist spot.
In the Mineirao Stadium which witnessed the landslide defeat, fans were expelled by police after they tried to destroy public property.
Meanwhile, as sadness gripped most of the city of Sao Paulo which had been preparing to celebrate after the match, rioters set fire to 15 buses in the garage of a transport firm, company sources said.
The incident occurred half hour after the end of the match in Belo Horizonte, the most sounding defeat ever for a Brazilian national team, which was branded as "shameful" by the press.
Two other buses were burned down in Sao Paulo overnight, while in the neighbouring town of Guarulhos, a group of strangers forced passengers to get off a bus and set it on fire.
Police said an appliance store was destroyed in the same town, leading to the arrest of two men and three teenagers.
Other incidents took place in the FanFest areas set up by FIFA in Brazilian World Cup host cities. Police used tear gas to break up a fight between fans in the northeastern city of Recife.
According to Brazilian media, some people were trampled by horses.
In Salvador, capital of the northeastern state of Bahia and one of the 12 venues of the World Cup, the FanFest, where 50,000 spectators had gathered, had to be suspended after riots and attempted assault.
In Curitiba, 15 buses were stoned and another was burned. Three people were arrested in Rio de Janeiro's Copacabana beach for creating confusion and panic among the crowd.