Ferdinando Cefalù (Marcello Mastroianni), an impoverished Sicilian nobleman, is married to Rosalia (Daniela Rocca), an unattractive but devoted wife. However, he is in love with his cousin Angela (Stefania Sandrelli), a much younger and attractive woman whom he sees only during the summer because her family sends her away to the city to a nunnery to receive her education. Besides his wife, he shares his life with his elderly parents and his spinster sister and her boyfriend who runs a funeral business; the family share their once stately palace with his uncles, who are slowly but surely eating away the remainders of the then rich estate of the Baron.
Aware that divorce is illegal in Italy at the time, Ferdinando spends his free time imagining several ways in which he can do away with his wife, such as throwing her into a boiling cauldron to turn her into soap or sending her into space in a rocket. At a beach, he has a daydream of his wife in quicksand and she is pulled under. After a chance encounter with Angela during a family trip, he discovers that she shares his feelings. With this, he resolves to carry out his plans and is inspired by a local story of a woman who killed her husband in a rage of jealousy to make his wife have an affair so that he can catch her in flagrante delicto, murder her, and receive a light sentence for committing an honour killing, studying very carefully the criminal code. As he goes along fleshing out his plan, he first needs to find a suitable man for his wife, which he finds in the local priest's godson, Carmelo Patanè, who has had feelings for Rosalia for years and was presumed dead in Africa during World War II. He then also procures the State Prosecutor's friendship with small favors. The final stage of his plan is arranging to have Carmelo's constant presence in his house, which is achieved by his interest in having his palace frescoes restored.
The plan takes a while to get off the ground, because Carmelo is very shy and Rosalia is more than a match in conjugal fidelity. Ferdinando is aware of the development of his plan because he has been taping all their conversations and has to ward off the help's infatuation with Carmelo. During his monitoring of the entire plan, Ferdinando discovers that Carmelo is actually married with three children and a philanderer who could be easily distracted by any other passing skirt. However, his plan turns out better than expected when Rosalia and Carmelo finally give in to their passion; but as he eavesdrops the tape runs out at the precise moment the adulterers arrange for their next illicit meeting. All Ferdinando knows is that it will take place the next evening.
Rosalia feigns to have a terrible headache and remains home while the rest of the family go out to the theatre to see the première of La Dolce Vita, a film so scandalous that no one wishes to miss it. Ferdinando sneaks out of the theatre and goes back to the palace, arriving just in time to see Rosalia running to the train station. He initially has to run out after her but still has to retrieve the gun to kill the couple; and as a result he misses the train and the lovers in it. He revisits his plan and the Criminal Code, which calls for a crime of passion to be executed in the heat of the moment or in defense of one's honor; this then means changing his plan and passing off as the cuckold.
All the while Angela has been writing to Ferdinando to assure him of her undying love no matter what; however, one of her letters is misdelivered to her father who dies of a stroke upon reading it. At the funeral, Ferdinando is approached by Mrs. Patanè who demands to know what he will do to avenge their situation. Since Ferdinando is still doing nothing, she spits in his face in front of the entire town, which gives him all that he needed: an open insult to the family's honor due to his wife's elopement. The local mafia boss offers to find the lovers within 24 hours, which he does. As Ferdinando goes to the lovers' hideout, he comes across Mrs. Patanè, who has just shot her husband, which actually leaves him in a worse position than before. As he sees no other choice, he follows in Mrs. Patanè's footsteps and finally kills his wife. During his trial he is actually defended by the State Prosecutor who blames the whole thing on Ferdinando's father and his lack of love when raising him as a boy. He spends no more than three years in jail and finally comes back home to find a loving Angela waiting for him.
In the film's epilogue, Ferdinando and Angela are sailing away on a sailboat, happily. Ferdinando states "life begins at 40" as the camera pans down, revealing Angela seductively rubbing her feet against the workman steering the boat.
This film won the Academy Award for Best Writing, Story and Screenplay - Written Directly for the Screen; it was nominated both for Best Actor in a Leading Role (Marcello Mastroianni) and for Best Director. The film was also entered into the 1962 Cannes Film Festival, where it won the prize for Best Comedy.Marcello Mastroianni as Ferdinando Cefalù
Daniela Rocca as Rosalia Cefalù
Stefania Sandrelli as Angela
Leopoldo Trieste as Carmelo Patanè
Odoardo Spadaro as Don Gaetano Cefalù
Margherita Girelli as Sisina
Angela Cardile as Agnese
Lando Buzzanca as Rosario Mulè
Pietro Tordi as Attorney De Marzi
Ugo Torrente as Don Calogero
Antonio Acqua as Priest
Bianca Castagnetta as Donna Matilde Cefalù
Ignazio Roberto Daidone
In 2008 Divorce Italian Style was turned into an opera by Giorgio Battistelli; as Divorce à l'Italienne, it was premiered by the Opéra national de Lorraine on September 30 of that year. Tenor Wolfgang Ablinger Sperrhacke took the role created by Mastroianni. Battistelli chose to set every female role, except for Angela, for low male voice; to that end, Bruno Praticò sang the role of Rosalia.