"It's wonderful that I can carry the flag for the Swiss delegation on my birthday," Federer said in a Swiss Olympic statement.
"It's well known that I still have a score to settle with the Olympics and being handed this honor for a second time will give me extra motivation."
Federer went into the Athens Games as a hot gold-medal favorite but was upset by Czech Republic's Tomas Berdych early in the tournament. This summer he and his Spanish archrival Rafael Nadal will both fight for their first Olympic titles.
Adam van Koeverden, the reigning Olympic and world champion in the 500m kayak singles, was chosen to be Canada's flag barer for the Beijing Olympics.
He beat out a list of candidates that included Olympic medal-winning diver Alexandre Despatie, nine-time Olympian equestrian rider Ian Millar, and gymnast Kyle Shewfelt, who recovered from two broken legs to make the team for Beijing.
Water-sport-strong Australia selected triple Olympic winning rower James Tomkins to carry its flag.
After winning last year's European championship in Spain, sporting powerhouse Russia named basketball forward Andrei Kirilenko its flag-bearer. The 27-year-old forward plays for the NBA's Utah Jazz and is one of his country's most prominent global athletes.
Another three basketball stars will join Kirilenko as flag bearers for their teams: Sarunas Jasikevicius from Lithuanian, Dirk Nowitzki from Germany and Argentina's Manu Ginobili are all scheduled to carry their national banners in Beijing.
Girl power
To pay tribute to China's most popular sport, three women's table tennis players will carry the flags for their countries.
Li Jia Wei, the Beijing-born paddler, will carry Singapore's flag (and try to help it win its first Olympic medal in nearly 50 years). As will Fukuhara Ai, the most popular Japanese player in China, will hoist Japan's. Jordan has also named women's table tennis player Zeina Shaban as its flag bearer.
Maitha bint Mohammed bin Rashid Al Maktoum, the daughter of Sheikh Mohammed bin Rashid Al Maktroum, will represent United Arab Emirates in taekwondo 67kg category and will carry her country's flag.
And Mexico chose diver Paola Espinosa Snchez, one of Mexico's most famous athletes, to lead the Olympic squad bearing the flag.