Flamengo's and Fluminense's supporters.
|City or region||Rio de Janeiro, State of Rio de Janeiro, Brazil|
|Teams involved||Flamengo, Fluminense|
|First contested||July 7, 1912|
|Most wins||Flamengo (132)|
Fla–Flu (truncation of Flamengo-Fluminense) is a football (soccer) match between cross-town rivals Flamengo and Fluminense. Matches take place in the 95,000-seat Maracanã Stadium, located near downtown Rio de Janeiro, in the city's Maracanã district. The world record football match attendance between clubs is a Fla 0-0 Flu with 194,603 (177,656 paid) in 1963.
The moniker Fla–Flu was coined by the journalist Mário Filho during the professionalization of Rio de Janeiro's football.
Flamengo is the most successful team in Rio State Championship by one championship. Flamengo has won it 32 times while Fluminense has won 31. Flamengo has won 5 Brazilian National Championships, as defined by the CBF, the 1987 Copa União (an independent league organised by the Club of 13) and 2 Brazilian Cups. Fluminense has won 4 Brazilian National Championships and 1 Brazilian Cup. Fluminense has won the Copa Rio, which it claims to be equivalent to an intercontinental club tournament. Flamengo has won one Libertadores Cup and one Intercontinental Cup, both in 1981. Fluminense is the only team in the world that holds the IOC's Olympic Cup ("Coupe Olympique" or "Taça Olímpica"), a non-competitive award for distinguished service in upholding the ideals of the Olympic Movement and to recognise the particular merits of institutions or associations and their services rendered to sport, conquered in 1949.
The rivalry between these two clubs began in October 1911, when a group of dissatisfied players from Fluminense left the club, and went to Flamengo, which at the time had no football department. The first Fla–Flu ever was played the following year, on July 7, 1912 at Laranjeiras stadium. Fluminense won this match 3-2, with 800 people in attendance.
On November 23, 1941, Flamengo and Fluminense disputed the Campeonato Carioca final, at Gávea Stadium. As the stadium is located in Lagoa neighborhood, the match was nicknamed Lagoa's Fla-Flu. The first half of the match ended 2-1 to Fluminense. Flamengo's Pirillo scored a goal in the 39th minute of the second half of the match, but Fluminense only needed a draw in the match, and won the competition. 15,312 people watched the match.
In 1991, the Campeonato Carioca final was again disputed between Flamengo and Fluminense. The first leg, played on December 13, ended in a 1-1 draw. In the second leg, played on December 19, Flamengo beat Fluminense 4-2. The Flamengo goals were scored by Uidemar, Gaúcho, Zinho and Júnior. Both Fluminense goals were scored by Ézio. Flamengo's Gaúcho was the top goalscorer of that competition.
In the Campeonato Carioca history, Fluminense beat Flamengo to the title in 1919, 1936, 1941, 1969, 1973, 1983, 1984 and 1995. Flamengo beat Fluminense in 1963, 1972 and 1991. The Carioca had many formats over the years.
One of the most famous matches  between the two clubs is the 1995 Campeonato Carioca final stage match, played on June 25 of that year at Maracanã stadium. In this match, Fluminense's Renato Gaúcho scored a belly goal, and his team won the match 3-2. Fluminense finished the stage with 33 points, winning the title, and Flamengo finished one point behind its rival, losing the championship in the year of its centenary.
The 2004 Campeonato Carioca had two matches played between Flamengo and Fluminense. On February 1, Flamengo won by 4-3, after Fluminense scored 3-1 in the first half. On February 21, Flamengo beat Fluminense 3-2, which gave Flamengo the Taça Guanabara title of that year.
Highest attendances in Fla-Flu
- Flamengo - Fluminense 0-0, 194,603 (177.656 paid), December 12, 1963.
- Flamengo - Fluminense 2-3, 171,599, June 15, 1969.
- Flamengo - Fluminense 0-0, 155,116, May 16, 1976.
- Flamengo - Fluminense 0-1, 153,520, December 16, 1984.
- Flamengo - Fluminense 0-2, 138,599, August 2, 1970.
- Flamengo - Fluminense 1-1, 138,557, April 22, 1979.
- Flamengo - Fluminense 5-2, 137,002, April 23, 1972.
- Flamengo - Fluminense 2-1, 136,829, September 7, 1972.
- Flamengo - Fluminense 3-3, 136,606, October 18, 1964.
- Flamengo - Fluminense 1-0, 124,432, September 23, 1979.
As of September, 2012:
Latest match: Fluminense 2 x 3 Flamengo (played on August 11th, 2013) (2013 Campeonato Brasileiro) 
- Enciclopédia do Futebol Brasileiro, Volume 1 - Lance, Rio de Janeiro: Aretê Editorial S/A, 2001.
- ´´Placar Magazine´´, 2005/May, The Big Classics, and Cheiro de 2004 no ar - AOL Esportes (March 29, 2005)
- Enciclopédia do Futebol Brasileiro, Volume 2 - Lance, Rio de Janeiro: Aretê Editorial S/A, 2001.
- A Taça Olímpica (1949) - Flumania
- O Flamengo nasceu do Fluminense - Museu dos Esportes
- Passion, carnival and crazy goals - FIFA website (July 13, 2001)
- O mais querido do Brasil!! - Flamengonet (November 13, 2004)
- Coração de torcedor - No Olhar (January 10, 2004)
- Fla-Flu history at Grandes Clássicos
- Renato comemora 8 anos do gol de barriga Estadão Esportes (June 25, 2003)
- Best Attendances in Fla-Flu
- Fla-Flu Derbies