The screenplay is based primarily on Guevara's travelogue The Motorcycle Diaries by Ernesto "Che" Guevara, with additional context supplied by Back on the Road: A Journey Through Latin America by Alberto Granado. Guevara is played by Mexican actor Gael García Bernal, and Granado by the Argentine actor Rodrigo de la Serna, who is a second cousin to Che Guevara on his maternal side. Directed by Brazilian director Walter Salles and written by Puerto Rican playwright José Rivera, the film was an international co-production between production companies from Argentina, the United States, Germany, the United Kingdom, Chile, Peru and France. The film's executive producers were Robert Redford, Paul Webstera, and Rebecca Yeldham; the producers were Edgard Tenenbaum, Michael Nozik, and Karen Tenkoff; and the co-producers were Daniel Burman and Diego Dubcovsky.
In 1952, a semester before Ernesto "Fuser" Guevara is due to complete his medical degree, he and his older friend Alberto, a biochemist, leave Buenos Aires in order to travel across the South American continent in search of fun and adventures. While there is a goal at the end of their journey-- they intend to work in a leper colony in Peru-- the main purpose is tourism. They want to see as much of Latin America as they can, more than 8,000 miles in just a few months, and also bed as many Latin American women as will fall for their pick-up lines. Their initial method of transport is Alberto's ancient and leaky but functional Norton 500 motorcycle christened La Poderosa ("The Mighty One").
Their route is ambitious. They head south, aim to cross the Andes, travel along the coast of Chile, across the Atacama Desert and into the Peruvian Amazon and reach Venezuela just in time for Alberto's 30th birthday, April 2nd. Due to La Poderosa's breakdown, they are forced to travel at a much slower pace, and make it to Caracas in July.
During their expedition, Guevara and Granado encounter the poverty of the indigenous peasants, and the movie assumes a greater seriousness once the men gain a better sense of the disparity between the "haves" and "have-nots" of Latin America. In Chile, the pleasure travelers encounter a couple forced onto the road because of their communist beliefs. In a fire-lit scene, Ernesto and Alberto admit to the couple that they are not out looking for work as well. The duo accompany the couple to the Chuquicamata copper mine, and Guevara becomes angry at the treatment of the workers. There is also an instance of recognition when Ernesto, on a river ship, looks down at the poor people on the smaller boat hitched behind. Ernesto's connection to people in need is visceral and tactile throughout the film. It shows in the way he smoothes the forehead of a terminally ill woman who cannot afford a proper doctor.
However, it is a visit to the Incan ruins of Macchu Picchu that inspires something in Ernesto. He wonders how the highly advanced culture gave way to the urban sprawl of Lima. His answer is that the Spanish had guns.
In Peru, they volunteer for three weeks at the San Pablo leper colony. There, Guevara sees both physically and metaphorically the division of society between the toiling masses and the ruling class (the staff live on the north side of a river, separated from the lepers living on the south). Guevara also refuses to wear rubber gloves during his visit choosing instead to shake bare hands with startled leper inmates.
At the end of the film, after his sojourn at the leper colony, Guevara confirms his nascent egalitarian, anti-authority impulses, while making a birthday toast, which is also his first political speech. In it he evokes a pan-Latin American identity that transcends the arbitrary boundaries of nation and race. These encounters with social injustice transform the way Guevara sees the world, and by implication motivates his later political activities as a revolutionary.
Guevara makes his symbolic "final journey" that night when despite his asthma, he chooses to swim across the river that separates the two societies of the leper colony, to spend the night in a leper shack, instead of in the cabins of the doctors. This journey implicitly symbolizes Guevara's rejection of wealth and aristocracy into which he was born, and the path he would take later in his life as a guerrilla, fighting for what he believed was the dignity every human being deserves.
As they bid each other farewell, Alberto reveals that his birthday was not in fact April 2, but rather August 8, and that the stated goal was simply a motivator: Ernesto replies that he knew all along. The film is closed with an appearance by the true life 82-year-old Alberto Granado, along with pictures from the actual journey and a mention of Che Guevara's eventual 1967 CIA-assisted execution in the Bolivian jungle.
The film screened at many other film festivals, including: the Auckland International Film Festival, New Zealand; the Copenhagen International Film Festival, Denmark; the Espoo Film Festival, Finland; the Telluride Film Festival, United States; the Toronto Film Festival, Canada; the Vancouver International Film Festival, Canada; the Celebrating Literature in Cinema Filmfestival Frankfurt, Germany; the Morelia Film Festival, Mexico; and others.
Paula Nechak of the Seattle Post-Intelligencer praised director Walter Salles by remarking that he "presents the evolutionary course of a young man who coincidentally became the dorm-room poster boy for an idealistic generation, and captures the lovely, heart-and-eye-opening ode to youthful possibility with affection and compassion. While Washington Post critic Desson Thomson lent praise for the films starring actor by observing that "what Bernal and this well-wrought movie convey so well is the charisma that would soon become a part of human history, and yes, T-shirts.
Among the film's detractors was Roger Ebert of the Chicago Sun-Times, who described the film's positive reviews as "a matter of Political Correctness, I think; it is uncool to be against Che Guevara." Ebert also criticized the film's characterization: "seen simply as a film, The Motorcycle Diaries is attenuated and tedious. We understand that Ernesto and Alberto are friends, but that's about all we find out about them; they develop none of the complexities of other on-the-road couples... Nothing is startling or poetic. Jessica Winter of The Village Voice criticized the film's simplistic representation of the peasantry, describing "the young men's encounters with conscience-pricking, generically noble locals" who are occasionally assembled "to face the camera in a still life of heroic, art-directed suffering".
The online review aggregator Metacritic records that 75% of 67 reviews were positive, while Rotten Tomatoes records 82% of 148 reviews. The film also received a standing ovation at the 2004 Sundance film festival.