Romario received more than 4.5 million votes in Rio de Janeiro, the most ever in the state. He had 63 percent of the total, ahead of former Rio mayor Cesar Maia, his closest contender with 20 percent.
Romario was an active congressman the past four years, a fierce critic of the money spent on the World Cup. He has a daughter with a disability, and one of his main causes was to improve conditions for the disabled.
The 48-year-old World Cup winner said he was proud to have "dribbled past poverty" to make history as a former slum resident who made it to the senate.