"La balsa" (pronounced [la ˈβalsa]; Spanish for "The raft") is the debut single by the Argentine band Los Gatos, released on July 3, 1967 on Vik, a subsidiary of RCA Victor. Formed in 1967 after the disbandment of Los Gatos Salvajes, Los Gatos were the house band of the bar La Cueva, which became a popular meeting place for rock enthusiasts and the birthplace of Argentine rock—known locally as rock nacional (Spanish for "national rock"). During the mid-1960s, Buenos Aires was experiencing a cultural blossoming characterized by innovations in modern art, literature and cinema, largely driven by a burgeoning youth subculture that adhered to the countercultural phenomenon of the decade. The underground had its epicenter in La Cueva, Plaza Francia and the Torcuato di Tella Institute, and identified with British Invasion music and the sexual revolution. "La balsa" was famously written by Litto Nebbia—lead vocalist of the band—and Tanguito (credited as Ramsés) on May 2, 1967 in the men's toilet of La Perla de Once, another bar frequented by the group. At the time, Argentina was under a military dictatorship led by Juan Carlos Onganía, which regularly imprisoned and persecuted these young bohemians.

Released alongside the B-side "Ayer Nomás", "La balsa" became a major hit in Argentina and various Latin American countries, selling around 250,000 copies. It is a melodic, beat-influenced song, with prominent use of a Farfisa electronic organ and bossa nova elements attributed to Nebbia. Its sound—and commercial impact—reflected the loss of popularity of the nueva ola phenomenon and American rock 'n' roll, which began to be perceived as trivial. The success of "La balsa" was an unprecedented feat for Spanish-language rock (rock en español), as it established its commercial viability at a time when the use of Spanish lyrics was discouraged. Its release is generally considered to be the origin of Argentine rock, paving the way for bands such as Almendra and Manal—along with Los Gatos, these bands are considered the foundational trilogy of the style. The popularity of "La balsa" turned Argentine rock into a widespread youth culture phenomenon, and was followed by the appearance of the first magazines, independent record labels and music festivals of the movement. The song also became an anthem for the burgeoning Argentine hippyism, which grew in size and influenced this first stage of rock nacional.

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