In post-World War II Rome, Antonio Ricci is desperate for work to support his wife Maria, his son Bruno and his small baby. He is offered a job posting advertising bills but tells Maria that he cannot accept because the job requires a bicycle. Maria resolutely strips the bed of her dowry bedsheets‍—‌prized possessions for a poor family‍—‌and takes them to the pawn shop, where they bring enough to redeem Antonio’s pawned bicycle.

On his first day of work, Antonio is atop a ladder when a young man steals his bicycle. Antonio runs after him but is thrown off the trail by the thief’s confederates. The police file Antonio’s complaint but say that there is little they can do.

Advised that stolen goods often surface at the Piazza Vittorio market, Antonio goes there with several friends and Bruno. They find a bicycle frame that might be Antonio’s, but the vendors refuse to allow them to examine the serial number. They call over a carabiniere, who orders the vendors to allow him to read the serial number. It does not match that of the missing bicycle, but the officer won’t allow them to examine it for themselves.

At the Porta Portese market, Antonio and Bruno spot the thief with an old man. The thief eludes them and the old man feigns ignorance. They follow him into a church where he too slips away from them.

Antonio pursues the thief into a brothel, whose denizens eject them. In the street, hostile neighbors gather as Antonio accuses the thief, who conveniently falls into a fit for which the crowd blames Antonio. Bruno fetches a policeman, who searches the thief’s apartment without success. The policeman tells Antonio the case is weak‍—‌Antonio has no witnesses and the neighbors are certain to provide the thief with an alibi. Antonio and Bruno leave in despair amid jeers and threats from the crowd.