The names honour Brazilian musicians and partners Vinicius de Moraes and Tom Jobim. They were exponents of Bossa Nova music and creators of the famous song "The Girl from Ipanema."
The Rio organizing committee offered three choices for the mascot pairs, and it said Vinicius and Tom were chosen in a vote in which about 320,000 people participated.
Vinicius is a yellow cat-like creature that represents Brazil's fauna, and Tom is a bushy-headed figure reminiscent of the country's diverse flora.
The mascots will head a merchandising effort to sell about $400 million in Olympic-branded products.