A bitter campaign in which he was accused of unfairly using the country's oil wealth was followed by a long wait for the results.
Finally, fireworks exploded over Caracas amid car horn-honking by elated supporters waving flags outside the presidential palace.
With 90% of votes counted, Mr Chavez had more than 54% to 45% for challenger Henrique Capriles, a former state governor who unified the opposition.
But Mr Capriles' promises to seriously address violent crime, streamline a patronage-bloated bureaucracy and end corruption proved inadequate against Mr Chavez's charisma, well-oiled political machine and a legacy of putting the poor first with generous social welfare.
Mr Chavez rallied thousands of supporters from a balcony of the presidential palace, holding up a sword that once belonged to 19th- Century independence hero Simon Bolivar.
"The revolution has triumphed!" Mr Chavez told the crowd after his third re-election and almost 14 years in office.