While widely criticized upon initial release, Los olvidados received Best Director at the 1951 Cannes Film Festival.

One day, El Jaibo comes to talk with him about their secret and, unbeknownst to Pedro, steals a customer's knife from the blacksmith's table.

Pedro is accused of the crime and sent to a juvenile rehabilitation program, the "farm school", where he gets into a fight and kills two chickens.

[4][5] At the International Cinematographic Festival in Saltillo, Coahuila, Mexico, on 3 February 2011, the last surviving member of the cast, Alfonso Mejía (Pedro), introduced the alternative ending to the film.

Thematically, Los Olvidados is similar to Buñuel's earlier Spanish film, Land Without Bread.

Los Olvidados is especially interesting because although "Buñuel employed [...] elements of Italian neorealism", a concurrent movement across the Atlantic Ocean marked by "outdoor locations, nonprofessional actors, low budget productions, and a focus on the working classes", Los Olvidados is not a neorealist film (Fernandez, 42).

"Neorealist reality is incomplete, conventional, and above all rational", Buñuel wrote in a 1953 essay titled "Poetry and Cinema".

Buñuel does not romanticize the characters, and even the abused blind man is revealed to have cruel habits of preying on children and selling fake elixirs.

Film historian Carl J. Mora has said of Los olvidados that the director "visualized poverty in a radically different way from the traditional forms of Mexican melodrama.

Buñuel's street children are not 'ennobled' by their desperate struggle for survival; they are in fact ruthless predators who are not better than their equally unromanticized victims".

[9] Journalist Verónica Calderón, in an article published on 14 August 2010 in the Spanish newspaper El País, collects statements by Morelia Guerrero, daughter of Mexican journalist and writer Jesús R. Guerrero (Numarán, Michoacán, 1911–1979), in which Morelia points out that the script and the film are based on a novel written by her father, entitled Los Olvidados, published in 1944, with a prologue by Mexican writer José Revueltas.

[12] Juan Carlos Ibáñez and Manuel Palacio write, "The film was so harsh and innovative, so critical and daring in its statements that during its first screenings, spectators openly aired their indignation towards the features of Mexican identity presented by Buñuel.

[19] Los Olvidados has been cited as an influence on films such as Pixote (1980), Amores perros (2000), and City of God (2002).